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Scientific Data Documentation
National Survey of Ambulatory Surgery, 1994
National Survey of Ambulatory Surgery 
Abstract                                
This material provides documentation for users of the 1994 NSAS Public Use 
Data Tape. The NSAS was implemented by the National Center for Health Statistics 
(NCHS)in 1994.  It covers ambulatory surgery procedures performed in hospitals 
and free-standing ambulatory surgery centers in the United States. 
Section I describes the survey and includes information on the history and scope 
of the NSAS; the survey methodology, data collection and medical coding procedures; 
population  estimates, measurement errors, and sampling errors. 

Section II provides technical details of the tape. 
Section III provides a detailed description of the contents of each data record.
Appendix A defines certain terms used in this document; Appendix B contains the 
ICD-9-CM Addenda; Appendix C provides population estimates to allow the user 
to calculate rates; and Appendix D provides unweighted and weighted frequencies 
for selected descriptive variables.
TABLE OF CONTENTS
Section I.   Description of the National Survey of Ambulatory Surgery
Section II.  Technical Description of Tape 
Section III. Record Format:  Location and Coding of Data Elements
Appendix A:  Definitions of Certain Terms Used in This Document
Appendix B:  ICD-9-CM Addenda
Appendix C:  Population Estimates
Appendix D:  Unweighted & Weighted Frequencies
             of Selected NSAS Variables
I.  Description of the National Survey of Ambulatory Surgery
Introduction

This document describes the 1994 National Survey of Ambulatory Surgery (NSAS)
and provides information for users of the 1994 NSAS public use data file.
This survey, conducted by the National Center for Health Statistics (NCHS) and
implemented in 1994, covers ambulatory surgery procedures performed in hospitals and
free-standing ambulatory surgery centers in the United States.  A brief description of
the survey design and data collection procedures is given below.  A more detailed
description of the survey design, data collection procedures, and the estimation process
will be published in a forthcoming report from the NCHS.  
History

The National Survey of Ambulatory Surgery was undertaken to obtain information
about the use of ambulatory surgery.  Ambulatory, or outpatient, surgery
has increased in the United States since the early 1980's.  Two major reasons for this
increase were advances in medical technology and cost containment initiatives.
On the medical side, many surgeries performed for hospital inpatients have moved to
outpatient settings, in part because improvements in anesthesia and better analgesics for
relief of pain have made surgery less complex and risky (1).  Also, minimally invasive
and non-invasive procedures, such as laser surgery, laparoscopy, and endoscopy, have
been developed and are being performed with increasing frequency. 
On the cost side, concern about rising health care costs led to changes in the Medicare
program that encouraged the use of ambulatory surgery (2).  In 1982 the Medicare
program was expanded to cover care in ambulatory surgery centers.  In 1983, a
prospective payment system based on diagnosis-related groups (DRG's) was adopted
for hospital inpatient care.  This system created strong financial incentives for hospitals
to perform less complex surgery in an ambulatory setting.  In the mid-1980's, the peer
review organizations for Medicare established outpatient settings as the norm for
certain surgeries and denied Medicare payment for hospital admissions deemed
inappropriate or medically unnecessary.  Many State Medicaid plans and private
insurers followed the lead of the Medicare program and adopted similar policies. 
As these changes went into effect, freestanding ambulatory surgery centers increased in
number, from 239 centers that performed 380,000 procedures in 1983, to over 1,800
centers performing more than 3.2 million procedures ten years later (3).  The number
of ambulatory surgery procedures done in hospitals and freestanding settings combined
rose from 5.4 million in 1983 to 16.2 million in 1993 (4).
The National Hospital Discharge Survey (NHDS), which has been conducted by the
National Center for Health Statistics every year since 1965, includes information on
procedures performed on inpatients (5).  The NHDS remains a good source of data for
surgical procedures, such as open-heart surgery or cesarean sections, that must be done
on an inpatient basis.  But for surgeries that can be performed on an ambulatory basis,
NHDS estimates are incomplete.  Thus the National Survey of Ambulatory Surgery was
undertaken to provide data on the increasing use of this type of health care.
SURVEY METHODOLOGY
Source of the Data

The NSAS covers ambulatory surgery procedures performed in hospitals and free-
standing ambulatory surgery centers (FSASC).  The hospital universe includes
noninstitutional hospitals exclusive of Federal, military, and Department of
Veterans Affairs hospitals, located in the 50 States and the District of Columbia.  
Only short-stay hospitals (hospitals with an average length of stay for all patients 
of less than 30 days) or those whose specialty is general (medical or surgical) or 
children's general are included in the survey.  These hospitals must also have six 
beds or more staffed for patient use. The universe definition is the same as that 
used for the National Hospital Discharge Survey.  The sampling frame for the hospital 
universe consisted of eligible hospitals listed in the 1993 SMG Hospital Market 
Database (6).
The universe of freestanding facilities includes FSASCs that are regulated by the States
or certified by HCFA, the Health Care Financing Administration, for Medicare
participation.  The sampling frame consisted of facilities listed in the 1993 Freestanding
Outpatient Surgery Center Database (7) and Medicare-certified facilities included in the
HCFA Provider-of-Services (POS) file (8).  Facilities specializing in dentistry,
podiatry, abortion, family planning, or birthing are excluded.  However, these
procedures are not excluded from in-scope locations.  A detailed description of the
development and operation of the NSAS will be provided in a forthcoming report.
Sample design and data collection--The NSAS samples facilities using a multi-stage
probability design with some facilities selected with certainty and others sampled with
varying selection probabilities.  Independent samples of hospitals and free-standing
ambulatory surgery centers were drawn.  The sample includes with certainty facilities
which perform a high volume of ambulatory surgeries annually.  Non-certainty
facilities are selected using a stratified, cluster design, where the clusters are 198
primary sampling units (PSUs) that comprise the sample of PSUs used in the 1985-1994
National Health Interview Survey (NHIS).  PSUs are counties or groups of counties, or
county equivalents, or towns and townships (the latter in New England and Hawaii).  
Noncertainty facilities were stratified by facility type (hospital versus freestanding),
ambulatory surgery status of hospitals  (i.e. whether or not the hospital performed such
surgery), facility specialty, and geographic region.  From each stratum containing
fewer than six facilities, up to three facilities were selected by means of systematic
random sampling, with selection probabilities proportional to size, where size is the
number of ambulatory surgeries performed annually.  For strata containing six or more
facilities, first stage sampling involved selection of 112 PSUs, which are a probability
subsample of the 198 PSUs in the 1985-94 NHIS sample.  Some of these PSUs were
sampled with certainty.  Selection of noncertainty PSUs was performed within PSU
strata defined within the four geographic regions by the number of people in the 1980
Census of Population and NHIS stratification variables.  From each PSU stratum, the
PSUs were selected with probability proportional to the projected 1985 population. 
The hospital sample is clustered within a probability subsample of 112 of those PSUs.   
The second stage of the cluster design consisted of selection of non-certainty facilities
from the sampled PSUs, using systematic random sampling with probabilities propor
tional to the annual number of ambulatory surgeries performed.  For both hospitals and
FSASCs, up to three facilities of each type and specialty were selected from each non-
certainty PSU and up to 15 facilities were selected across the combined certainty PSUs
in each region.  For the stratum of hospitals which, according to the sampling frame
data, did not have ambulatory surgery, a national sample of 50 hospitals was selected to
permit estimates of surgery in hospitals that either change their status or differ from
frame data.  Any sampled facility which performed less than 50 ambulatory surgeries in
the year prior to the data collection year was considered out-of-scope for the data
collection year.
Within sampled facilities, a sample of ambulatory surgery visits was selected using a
systematic random sampling procedure.  Selection of visits within each facility was
performed separately for each location where ambulatory surgery is performed.  These
locations include: main operating rooms, dedicated ambulatory surgery units, cardiac
catherization laboratories, laser procedure rooms, endoscopy and laparoscopy rooms,
etc.  Locations within facilities that specialize in or are dedicated to inpatients, den
tistry, abortion, podiatry, pain block, or small procedures are excluded.  However, as
mentioned above, these procedures are not excluded from in-scope locations.  
Following selection of ambulatory surgery visits, data was abstracted from the medical
record for each visit.  The Medical Abstract Form used in data collection is shown in
Figure 1.  It contains items relating to the personal characteristics of the patient,
including birth date or age, sex, race, zipcode, but not name and address; administra
tive information, including the date of the surgery, dispostion of the patient, and
medical record number; principal and other additional expected sources of payment;
and medical information, including diagnoses and surgical and nonsurgical procedures
performed. The medical record number, date of birth, and patient zip code, are
confidential information and are not available to the public.
Response Rate

The 1994 NSAS sample included 333 FSASCs from the 1,732 facilities in the 1993 
FSASC sampling frame; and 418 hospitals from the 6,267 listed in the 1993 hospital 
sampling frame.  Of the 751 sampled facilities, 134 were found to be out-of-scope 
for the NSAS and 126 others were nonresponding in 1994. 
Medical Coding and Edit

The medical information abstracted from the sampled medical records was coded centrally 
by NCHS contract staff.  A maximum of seven diagnostic codes and six procedure codes 
was assigned for each sampled abstract.  The system currently used for coding the 
diagnoses and procedures on the medical abstract forms is the International Classification 
of Diseases, 9th Revision, Clinical Modification, or ICD-9-CM (9). 
Following conversion of the data on the medical abstract to computer tape, a final
medical edit was accomplished by computer inspection and by a manual review of
rejected records.  Priority was given to medical information in the editing decision.
Users of the NSAS diagnostic and/or procedure data must take into account annual
ICD-9-CM addenda.  The addenda lists new codes, new fourth or fifth digits to existing
codes, as well as other modifications.  Changes go into effect October 1 of the calendar
year.  However, in order to preserve consistent coding throughout the data year, the
NSAS coding for 1994 data is consistent with the ICD-9-CM and the Addenda through
October 1, 1993.   Appendix B lists the changes for 1986 through 1993.
Population Estimates

Appendix C shows population estimates provided by the U.S. Bureau of the Census.  The 
estimates are of the U.S. civilian resident population on July l of the data year.  
These population estimates are consistent with those published in Current Population 
Reports, Series P-25; however, they are not official population estimates of the 
Bureau of the Census.
Figure 1.
Medical abstract for the 1994 National Survey of Ambulatory Surgery
Measurement Errors and Limitations of the Data

As in any survey, results are subject to nonsampling or measurement errors, which 
include errors due to facility nonresponse, missing abstracts, information 
incompletely or inaccurately recorded on abstract forms, and processing errors.
In a very small number of records, the age or sex of the patient was missing.  For these
records, a legitimate value was imputed in such a way as to preserve the original,
known distribution of the variable.  Fewer than one percent of the records have an
imputed age or sex value.  
Forty-three percent of the records were missing a value for race of the patient.  No
attempt was made to impute for these missing values.
The determination of whether an ambulatory surgery facility is a hospital or a free
standing center is based on the SMG universe from which the facility is selected.  In
most cases it is apparent whether a facility is a hospital or a freestanding ambulatory
surgery center, but some facilities are not easily classified.  For example, a "freestand
ing" facility may be owned by a hospital but located some distance away.  If such a
facility is separately listed in the 1993 SMG Freestanding Outpatient Surgery Center
Database and is selected into the NSAS sample from this universe, it is considered a
freestanding facility. 
The distinction between ambulatory and inpatient surgery is not always clear.  Accord
ing to the 1994 NSAS, an estimated 1.6 percent of ambulatory surgery visits were for
patients subsequently admitted to the hospital as inpatients.  Some of these patients had
procedures which are currently performed exclusively on inpatients, such as coronary
artery bypass graft, in addition to diagnostic procedures such as cardiac catheterization. 
These cases and their suspected "inpatient" procedures have not been eliminated
because they are operationally part of the survey design.   It is left to the prerogative of
the researcher whether or not to include these procedures in an analysis.
Sampling errors

Statistics from the NSAS are derived by a multistage estimation procedure that produces 
essentially unbiased estimates.  The estimation procedure has three basic components: 
(a) inflation by reciprocals of the probabilities of sample selection, (b) adjustment for 
nonresponse, and (c) population weighting ratio adjustments. 
The standard error of a statistic is primarily a measure of sampling variability that
occurs by chance because only a sample rather than the entire universe is surveyed. 
The relative standard error of the estimate is obtained by dividing the standard error by
the estimate itself.  The resulting value is multiplied by 100, so the relative standard
error (RSE) is expressed as a percent of the estimate.  Estimates of sampling variability
were calculated with SUDAAN software, which computes standard errors by using a
first-order Taylor series approximation of the deviation of estimates from their expected
values.  A description of the software and the approach it uses has been published (10).
Relative Standard Errors for Aggregate Estimates
Table 1 presents parameter estimates to be used in formulae for deriving the
approximate relative standard errors for aggregate estimates.  To provide error
estimates that would be applicable to a wide variety of statistics, numerous variances
were calculated and the best fit formula was derived.  The formula is based on an
empirically determined relationship between the size of an estimate X and its relative
variance.  The relative standard error is then derived by taking the square root of the
relative variance.  The relative standard error of an estimate X [RSE(X)], expressed as
a percent, may be calculated from the formula:

      RSE (X)~=~100~*~~SQRT { a~+~b/X } 
      with a and b provided in Table 1.
For example, in 1994 the estimated number of ambulatory surgery visits to hospitals
and free-standing ambulatory surgery centers by persons aged 65 and over with a first-
listed diagnosis of cataracts (ICD-9-CM code 366.0) was 1,536,000.  Using the
applicable constants from Table 1 for estimates by age produces:

      RSE (1,536,000)~=~100~*~SQRT {.00641~+~(406.832/1,536,000)}
                     RSE(1,536,000) = 8.17 %
The relative standard error for the estimate of interest is 8.17 percent.  From this the
standard error is obtained by multiplying the relative standard error by the estimate:
      SE(1,536,000) = 1,536,000 * 8.17 % = 125,491
The standard error can be employed to generate confidence intervals for statistical
testing.  In this example, the 95% confidence interval for the estimate of the total
number visits by persons aged 65 and over with a first-listed diagnosis of cataracts is:
      (1,536,000 - 2*125,491)<-> (1,536,000 + 2*125,491)
                   1,285,018 <-> 1,786,982
Relative Standard Error for Estimates of Percents
Approximate relative standard errors for estimates of percents may be calculated from
Table 1 also.  The relative standard error for a percent, 100 p (0<p<1), (expressed as
a percent), may be calculated using the formula:
      RSE(p)~=~100~*~ SQRT { b~*~(1~-~p)/(p~*~X) } 
      where 100p is the percent of interest, 
      X is the base of the percent, and b is the parameter value, 
      b, given in Table 1.
For example, in 1994 the estimated number of ambulatory surgery visits by persons in
the 65 and over age group was 6,083,000.  This is 32.3 percent of the estimated
18,850,000 visits for that year.  Using the applicable constants from Table 1 for
estimates by age produces:

      RSE(.323)~=~ 100~*~ SQRT {406.832~*~(1~-~.323)/(.323~*~18,850,000) } 
                      RSE (.323) = 0.673%
The relative standard error for the estimate of interest is 0.673 percent.  From this the
standard error is obtained by multiplying the relative standard error by the estimate:
      SE(.323) = .323 * 0.673 % = .0022       .        
The standard error can be employed to generate confidence intervals for statistical
testing.  In this example, the 95% confidence interval for the estimate of the percentage
of ambulatory surgery visits by persons in the 65 and over age group is:
              (.323 - 2*.0022) <-> (.323 + 2*.0022)
                       .319 <-> .327       
              or, equivalently,    31.9% <-> 32.7 %
Table 1.  Estimated parameters for relative standard error formulae for 
          National Survey of Ambulatory Surgery aggregate statistics by 
          statistic type:  United States, 1994
Characteristic First-Listed diagnoses All-Listed procedures  First-Listed diagnoses Hospital All-Listed
Procedures Hospital
First-Listed diagnoses  Freestanding All-Listed procedures
Freestanding
  a b a b a b a b a b a b
Total 0.00300 936.205 0.00314 1042.899 0.00365 937.294 0.00398 979.808 0.01812 246.302 0.01420 756.815

Sex

                       
Male 0.00584 243.411 0.00523 374.805 0.00703 259.441 0.00634 400.074 0.01973 148.898 0.02388 111.244
Female 0.00322 744.535 0.00376 617.095 0.00396 765.854 0.00468 609.192 0.01840 194.161 0.01200 581.791

Age

                       
Under 15 years 0.01611 65.118 0.00971 221.957 0.01693 94.812 0.01151 232.069 0.05864 9.702 0.03108 86.170
15-44 years 0.00465 422.787 0.00402 650.560 0.00529 467.627 0.00441 733.864 0.01948 148.963 0.01980 208.036
45-64 years 0.00556 376.824 0.00749 168.935 0.00690 395.110 0.00975 118.059 0.01978 133.576 0.02466 131.183
65 years and up 0.00641 406.832 0.00434 572.577 0.00794 425.446 0.00588 577.976 0.03041 111.598 0.04404 1.419

Region

                       
Northwest 0.01351 985.293 0.01372 857.242 0.01636 999.603 0.06862 58.778 0.07817 58.884 0.06862 58.778
Midwest 0.01064 644.607 0.01286 551.970 0.01040 653.985 0.09549 216.629 0.09150 165.353 0.09549 216.629
South 0.00982 404.800 0.00978 527.583 0.01281 346.622 0.04459 114.414 0.04682 90.105 0.04459 114.414
West 0.01790 457.195 0.01691 649.374 0.02522 411.895 0.06830 256.660 0.06264 174.679 0.06830 256.660
Source of  payment                        
Workers Comp 0.03854 31.835 0.03948 32.664 0.05125 26.390 0.05090 25.227 0.09805 6.784 0.08611 8.342
Medicare 0.00988 211.166 0.00918 136.914 0.01218 213.794 0.01160 137.695 0.03372 98.595 0.04712 1.439
Medicaid 0.01340 250.111 0.01087 344.152 0.01512 260.182 0.01266 348.100 0.07160 66.822 0.07934 36.771
Other Govt 0.04903 157.029 0.03933 226.740 0.05648 173.181 0.05198 215.742 0.21570 1.580 0.15983 23.475
Private Insurance 0.00336 777.159 0.00330 1127.336 0.00395 835.302 0.00390 1209.832 0.01397 252.713 0.01070 605.399
Self-Pay 0.02816 151.933 0.02076 293.085 0.03672 129.202 0.02781 246.163 0.10033 35.443 0.10972 39.263
NC/Other 0.07717 145.425 0.07357 149.427 0.08864 123.675 0.08341 154.664 0.25671 0.771 0.22214 0.792
Not Stated 0.06464 318.863 0.06675 381.220 0.08033 325.472 0.08540 297.599 0.20480 56.399 0.22074 115.011
Presentation of Estimates

Publication of estimates for the NSAS is based on the relative standard error 
of the estimate and the number of sample records on which the estimate is
based (referred to as the sample size).  Estimates are not presented in NCHS 
reports unless a reasonable assumption regarding the probability distribution 
of the sampling error is possible.
Based on consideration of the complex sample design of the NSAS, the following 
guidelines are used for presenting the NSAS estimates:
     If the sample size is less than 30, the value of the estimate is not reported.
     If the sample size is 30-59, the value of the estimate is reported but should 
     not be assumed reliable.
     If the sample size is 60 or more and the relative standard error is less than 30
     percent, the estimate is reported. 
     If the sample size is 60 or more but the relative standard error is over 30
     percent, the estimate is reported but should not be assumed reliable.
How to Use the Data Tape

The NSAS records are weighted to allow inflation to national or regional estimates.  
The weight applied to each record is found in tape location 21-25.  To produce
an estimate of the number of discharges, the weights for the desired records must 
be summed. 
Appendix D contains unweighted and weighted frequencies for selected descriptive variables
on the data tape.  These may be used as a cross-check when processing the data on the user's
system.
Questions

Questions concerning data on the tape should be directed to Maria Owings, Ph.D.,
Hospital Care Statistics Branch, Division of Health Care Statistics, National Center for 
Health Statistics, Presidential Building, Room 956, 6525 Belcrest Road, Hyattsville, Maryland 
20782, (301)-436-7125.
REFERENCES
1.   New surgical technologies reshape hospital strategies.  Hospitals 66(9):30-36, 38, 40-42. 1992.
2.   Leader S and Moon M. Medicare trends in ambulatory surgery.  Health Affairs Spring: 158-170.
     1989.
3.   Durant G.  Ambulatory surgery centers: surviving, thriving into the 1990's.  Medical Group
     Management Journal 36(2): 16-18, 20.  1989.
4.   SMG Marketing Group, Inc.  Outpatient surgery centers exceed 3 million cases.  SMG Market
     Letter 8(5).  1994.
5.   Graves EJ and Gillum BS.  1994 summary: National Hospital Discharge Survey.  Advance data
     from Vital and Health Statistics; no 278.  Hyattsville, Maryland: National Center for Health
     Statistics.  1996.
6.   SMG Marketing Group, Inc. Hospital Market Database.  Chicago: Healthcare Information
     Specialists.  April 1993.
7.   SMG Marketing Group, Inc. Freestanding Outpatient Surgery Centers Database.  Chicago:
     Healthcare Information Specialists.  1993.
8.   Health Care Financing Administration.  Provider of Services Public Use File.  Baltimore:  1993.
9.   Public Health Service and Health Care Financing Administration.  International Classification
     of Diseases, 9th Revision, Clinical Modification.  Washington: Public Health Service.  4th ed. 
     1991.
10.  Shah BV, Barnwell BG, Bieler GS.  SUDAAN User's Manual: Software for Analysis of
     Correlated Data, Release 6.40.  Research Triangle Park, NC: Research Triangle Institute.  1995.
II.  TECHNICAL DESCRIPTION OF TAPE
Data Set Name----------------------------------NSAS.YR1994
Number of REELS or CARTRIDGES------------------1
Number of Recording Tracks, REEL---------------9
Number of Recording Tracks, CARTRIDGE----------18
Density for REEL (bpi)-------------------------6,250
Density for CARTRIDGE (bpi)--------------------38,000
Language---------------------------------------EBCDIC
Parity-----------------------------------------Odd
Record Length----------------------------------97
Block Size-------------------------------------32,689
Number of Records------------------------------117,861

III.  RECORD FORMAT: Location and Coding of Data Elements
This section provides detailed information for each sampled record on the tape,
with a description of each item included in the record. Data elements are
arranged sequentially according to their physical location on the tape record. 
Data are derived from the abstract form; the SMG Hospital Market Tape is an
alternative source of data; some items are computer generated.
Item    Tape         Number of
Number	Location     Positions	   Item Description and Codes
______  ________     _________     __________________________
1	1-2	         2	       Survey Year: 94

2	3	         1	       Facility Type:
                                       1=Hospitals
                                       2=Free-Standing Ambulatory Surgery Center

3	4	         1	       Units for Age:
                                       1 = Years
                                       2 = Months
                                       3 = Days

4	5-6	         2	       Age in years, months, or days:
                                       If Units = Years:     0-99* 
                                       If Units = Months:   01-11
                                       If Units = Days:      00-31

5	7	         1	       Age Flag:
                                       1 = Value for Age was Imputed
                                       2 = Value for Age was Not Imputed

6	8	         1	       Sex:
                                       1 = Male
                                       2 = Female

7	9	         1	       Sex Flag:
                                       1 = Value for Sex was Imputed
                                       2 = Value for Sex was Not Imputed

8	10	         1	       Race:
                                       1 = White
                                       2 = Black
                                       3 = American Indian/Eskimo
                                       4 = Asian/Pacific Islander
                                       5 = Other
                                       9 = Race Not Stated

9	11   	         1	       Discharge Status:
                                       1 = Routine discharge to customary residence
                                       2 = Discharge to observation status
                                       3 = Discharge to recovery care center
                                       4 = Admitted to hospital as inpatient
                                       5 = Surgery cancelled or terminated
                                       6 = Other, specified
                                       9 = Discharge Status Not Stated

10	12-13	         2	       Month of Surgery:
                                       01 = January to
                                       12 = December

11	14	         1 	       Geographic Region
                                       1 = Northeast
                                       2 = Midwest
                                       3 = South 
                                       4 = West

12	15-16	         2	       Principal Expected Source of Payment
                                       0 = No Charge
                                       1 = Worker’s Compensation
                                       2 = Medicare
                                       3 = Medicaid
                                       4 = CHAMPUS
                                       5 = Other Government Payments
                                       6 = Blue Cross/Blue Shield
                                       7 = HMO/PPO
                                       8 = Other private or commercial insurance
                                       9 = Self Pay
                                      10 = Other, specified
                                      99 = No expected source of payment

13	17-18	        2	      Other Additional Source of Payment #1:
                                      Same coding as Principal ESOP

14	19-20  	        2	      Other Additional Source of Payment #2:
                                      Same coding as Principal ESOP

15	21-25	        5	      Analysis Weight: Use to Obtain Weighted Estimates

16-25	26-35	        10	      Type of Anesthesia: 10 types/options
                                      1 = Option Checked
                                      0 = Not Checked/Blank

16	26	        1	      Type of Anesthesia:  Topical/Local

17	27	        1             Type of Anesthesia:  IV Sedation

18	28	        1             Type of Anesthesia:  Monitored Anesthesia Care

19	29	        1             Type of Anesthesia:  Regional, Epidural

20	30	        1             Type of Anesthesia:  Regional, Spinal

21	31	        1             Type of Anesthesia   Regional, Retrobulbar block

22	32	        1             Type of Anesthesia:  Regional, Peribulbar block

23	33	        1             Type of Anesthesia:  Regional, Block

24	34	        1             Type of Anesthesia:  General

25	35	        1             Type of Anesthesia:  Other, specified

26-28	36-38	        3	      Anesthesia Administrator: 3 givers/options
                                      1 = Option Checked
                                      0 = Not checked/Blank

26	36              1             Anesthesia Administrator:
                                      Anesthesiologist

27	37              1             Anesthesia Administrator: 
                                      Certified Registered Nurse Anesthetist

28	38              1             Anesthesia Administrator:
                                      Other Surgeon/Physician

29	39-43	        5             Diagnosis ICD9-CM ** Code #1

30	44-48           5             Diagnosis ICD9-CM ** Code #2

31	49-53           5             Diagnosis ICD9-CM ** Code #3

32	54-58           5             Diagnosis ICD9-CM ** Code #4

33	59-63           5             Diagnosis ICD9-CM ** Code #5

34	64-68           5             Diagnosis ICD9-CM ** Code #6

35	69-73           5             Diagnosis ICD9-CM ** Code #7

36	74-77           4             Procedure ICD9-CM ** Code #1

37	78-81           4             Procedure ICD9-CM ** Code #2

38	82-85           4             Procedure ICD9-CM ** Code #3

39	86-89           4             Procedure ICD9-CM ** Code #4

40	90-93           4             Procedure ICD9-CM ** Code #5

41	94-97           4             Procedure ICD9-CM ** Code #6
------------------------------------------------------------------------------------------------------------------
* Ages 100 and over were recoded to 99.

** Codes are in compliance with the International Classification of Diseases, 9th Revision, Clinical Modification, 
(ICD-9-CM). For diagnosis codes, there is an implied decimal between positions 3 and 4.  For V-Codes and E-codes, the 
implied decimal is between positions 4 and 5.  For inapplicable 4th or 5th digits, a dash is inserted.  For procedure 
codes, there is an implied decimal between positions 2 and 3.  For inapplicable 3rd or 4th digits, a dash is inserted.
APPENDIX A
DEFINITION OF TERMS
Hospitals- Short-stay hospitals or hospitals whose specialty is general (medical or surgical), or
children's general.  Hospitals must have 6 beds or more staffed for patients use.  Federal hospitals 
and hospital units of institutions are not included.
Free- Standing Ambulatory Surgery Centers-Facilities listed in the 1993 Freestanding Outpatient
Surgery Center Database and Medicare-certified facilities included in the HCFA Provider-of-Services
(POS) file.  Facilities specializing in dentistry, podiatry, abortion, family planning, or birthing 
are excluded.
Ambulatory Surgery- Scheduled outpatient surgery performed in any of the following locations:
general or main operating room, satelitte operating room, cystoscopy room, endoscopy room, cardiac
catherterization lab, laser procedures room.
First-listed diagnosis- The coded diagnosis which is listed first on the face sheet of the medical record.
The number of first-listed diagnoses is equivalent to the number of ambulatory surgery visits.
Procedures- Surgical or nonsurgical operations, procedures, or special treatments listed by the
physician on the medical record.  In the NSAS, all terms listed on the face sheet (summary sheet) of
the medical record under the caption "operation," "operative procedures," "operations and/or special
treatment," and the like are transcribed in the order listed.  A maximum of six procedures is coded.
Rate of procedures- The ratio of the number of procedures during a year to the number of persons in
the civilian population on July 1 of that year.
Age- The age of the patient on the birthday prior to the date of surgery.
Population- Civilian population is the resident population excluding members of the Armed Forces.
Geographic region- Hospitals are classified by location in one of the four geographic regions of the
United States corresponding to those used by the U.S. Bureau of the Census:

 

Geographic Region   States included
Northeast.............Maine, New Hampshire, Vermont
                      Massachusetts, Rhode Island,
                      Connecticut, New York, New Jersey,
                      and Pennsylvania
Midwest..............Michigan, Ohio, Illinois, Indiana,
                     Wisconsin, Minnesota, Iowa,
                     Missouri, North Dakota,
                     South Dakota, Nebraska,
                     and Kansas
South..................Delaware, Maryland, District of Columbia,
                       Virginia, West Virginia, North Carolina,
                       South Carolina, Georgia, Florida, Kentucky,
                       Tennessee, Alabama, Mississippi, Arkansas,
                       Louisiana, Oklahoma, and Texas
West...................Montana, Idaho, Wyoming, Colorado, 
                       New Mexico, Arizona, Utah, Nevada, Washington, 
                       Oregon, California, Hawaii, and Alaska
APPENDIX B 
The International Classification of Diseases, 9th Revision, Clinical Modification, which is 
used for coding NSAS data, undergoes annual updating.  Assignment of new diagnostic and procedure
codes, fourth and fifth digit expansion of codes, as well as code deletions, are contained in 
addenda developed by the ICD-9-CM Coordination and Maintenance Committee and approved by the 
Director of NCHS and the Administrator of the Health Care Financing Administration.  Addenda to 
the ICD-9-CM become effective on October 1 of the calendar year and have been released for 1986 
through 1994. 
As described earlier in this document, all data collected for the 1994 NSAS were coded using
the third edition of the ICD-9-CM, which includes the addenda for 1986 through 1993.  Although the
October 1994 Addendum was available, it was decided not to implement those code changes, since the
other nine months of data were coded to the 1993 Addendum.  This was done in order to prevent
NSAS data users from mistaking partial year estimates for annual estimates. 
   
In order to assist users in data retrieval and analysis, a conversion table is provided that shows
the date of introduction of each new code and the previously assigned code equivalent, which had been
used for reporting the selected diagnosis or procedure prior to issuance of the new code.
DIAGNOSIS CODES


                               Effective		
Current code(s) assignment     October 1       Previous code(s) assignment	
			
008.00-008.09	                   1992	          008.0	
008.43-008.47	                   1992	          008.49	
008.61-008.69	                   1992	          008.6	
			
041.00-041.09	                   1992	          041.0	
041.10-041.19	                   1992	          041.1	
041.81-041.89	                   1992	          041.8	
			
042.0-042.9	                   1986	          279.19	
043.0-043.9	                   1986	          279.19	
044.0-044.9	                   1986	          279.19	
			
070.20-070.21	                   1991	          070.2	
070.30-070.31	                   1991	          070.3	
070.41-070.49	                   1991	          070.4	
070.51-070.59	                   1991	          070.5	
			
077.98-077.99	                   1993	          077.9	
		    	
078.10-078.11,078.19	           1993	          078.1	
			
078.88	                           1993	          078.89	
			
079.4 	                           1993	          079.8	
079.50-079.53,079.59	           1993	          079.8	
079.88-079.89	                   1993	          079.8	
079.98-079.99	                   1993	          079.9	
			
088.81,088.89	                   1989	          088.8	
			
088.82	                           1993	          088.89	
			
099.40-099.49	                   1992	          099.4	
099.50-099.59	                   1992	          078.89	
112.84-112.85	                   1992	          112.89	
			
114.4-114.5	                   1993	          114.3	
			
176.0-176.9	                   1991	          173.0-173.9	
			
203.00	                           1991	          203.0	
203.01	                           1991	          V10.79	
203.10	                           1991	          203.1	
203.11	                           1991	          V10.79	
203.80	                           1991	          203.8	
203.81	                           1991	          V10.79	
			
204.00	                           1991	          204.0	
204.01	                           1991	          V10.61	
204.10	                           1991	          204.1	
204.11	                           1991	          V10.61	
204.20	                           1991	          204.2	
204.21	                           1991	          V10.61	
204.80	                           1991	          204.8	
204.81	                           1991	          V10.61	
204.90	                           1991	          204.9	
204.91	                           1991	          V10.61	
			
205.00	                           1991	          205.0	
205.01	                           1991	          V10.62	
205.10	                           1991	          205.1	
205.11	                           1991	          V10.62	
205.20	                           1991	          205.2	
205.21	                           1991	          V10.62	
205.30	                           1991	          205.3	
205.31	                           1991	          V10.62	
205.80	                           1991	          205.8	
205.81	                           1991	          V10.62	
205.90	                           1991	          205.9	
205.91	                           1991	          V10.62	
			
206.00	                           1991	          206.0	
206.01	                           1991	          V10.63	
206.10	                           1991	          206.1	
206.11	                           1991	          V10.63	
206.20	                           1991	          206.2	
206.21	                           1991	          V10.63	
206.80	                           1991	          206.8	
206.81	                           1991	          V10.63	
206.90	                           1991	          206.9	
206.91	                           1991	          V10.63	
			
207.00	                           1991	          207.0	
207.01	                           1991	          V10.69	
207.10	                           1991	          207.1	
207.11	                           1991	          V10.69	
207.20	                           1991	          207.2	
207.21	                           1991	          V10.69	
207.80	                           1991	          207.8	
207.81	                           1991	          V10.69	
			
208.00	                           1991	          208.0	
208.01	                           1991	          V10.60	
208.10	                           1991	          208.1	
208.11	                           1991	          V10.60	
208.20	                           1991	          208.2	
208.21	                           1991	          V10.60	
208.80	                           1991	          208.8	
208.81	                           1991	          V10.60	
208.90	                           1991	          208.9	
208.91	                           1991	          V10.60	
			
237.70-237.72	                   1990	          237.7	
			
250.02	                           1993	          250.90	
250.03	                           1993	          250.91	
			
250.12	                           1993	          250.10	
250.13	                           1993	          250.11	
250.22	                           1993	          250.20	
250.23	                           1993	          250.21	
250.32	                           1993	          250.30	
250.33	                           1993	          250.31	
250.42	                           1993	          250.40	
250.43	                           1993	          250.41	
250.52	                           1993	          250.50	
250.53	                           1993	          250.51	
250.62	                           1993	          250.60	
250.63	                           1993	          250.61	
250.72	                           1993	          250.70	
250.73	                           1993	          250.71	
250.82	                           1993	          250.80	
250.83	                           1993	          250.81	
250.92	                           1993	          250.90	
250.93	                           1993	          250.91	
			
283.10-283.11,283.19	           1993	          283.1	
	  		
320.81-320.89	                   1992	          320.8	
			
337.20-337.22,337.29	           1993	          337.9	
			
344.81-344.89	                   1993	          344.8	
			
345.00-345.01	                   1989	          345.0	
345.10-345.11	                   1989	          345.1	
345.40-345.41	                   1989	          345.4	
345.50-345.51	                   1989	          345.5	
345.60-345.61	                   1989	          345.6	
345.70-345.71	                   1989	          345.7	
345.80-345.81	                   1989	          345.8	
345.90-345.91	                   1989	          345.9	
			
346.00-346.01	                   1992	          346.0	
346.10-346.11	                   1992	          346.1	
346.20-346.21	                   1992	          346.2	
346.80-346.81	                   1992	          346.8	
346.90-346.91	                   1992	          346.9	
			
355.71	                           1993	          354.4	
355.79	                           1993	          355.7	
			
371.82	                           1992	          371.89	
			
374.87	                           1990	          374.89	
			
403.00-403.01	                   1989	          403.0	
403.10-403.11	                   1989	          403.1	
403.90-403.91	                   1989	          403.9	
			
404.00-404.03	                   1989	          404.0	
404.10-404.13	                   1989	          404.1	
404.90-404.93	                   1989	          404.9	
			
410.00-410.02	                   1989	          410.0	
410.10-410.12	                   1989	          410.1	
410.20-410.22	                   1989	          410.2	
410.30-410.32	                   1989	          410.3	
410.40-410.42	                   1989	          410.4	
410.50-410.52	                   1989	          410.5	
410.60-410.62	                   1989	          410.6	
410.70-410.72	                   1989	          410.7	
410.80-410.82	                   1989	          410.8	
410.90-410.92	                   1989	          410.9	
			
411.81	                           1989	          410.9	
411.89	                           1989	          411.8	
			
429.71	                           1989	          410.0-410.9	
429.79	                           1989	          410.0-410.9	
			
433.00-433.01	                   1993	          433.0	
433.10-433.11	                   1993	          433.1	
433.20-433.21	                   1993	          433.2	
433.30-433.31	                   1993	          433.3	
433.80-433.81	                   1993	          433.8	
433.90-433.91	                   1993	          433.9	
			
434.00-434.01	                   1993	          434.0	
434.10-434.11	                   1993	          434.1	
434.90-434.91	                   1993	          434.9	
			
437.7	                           1992	          780.9	
			
440.20-440.22	                   1992	          440.2	
			
440.23	                           1993	          440.20 & 707.1 or 707.8 or 707.9	
440.24	                           1993	          440.20 & 785.4	
440.29	                           1993	          440.20	
			
441.6	                           1993	          441.1 & 441.3	
441.7	                           1993	          441.2 & 441.4	
			
446.20-446.21,446.29	           1990	          446.2	
451.82-451.84	                   1993	          451.89	
			
482.30-482.39	                   1992	          482.3	
482.81-482.89	                   1992	          482.8	
			
483.0	                           1992	          483	
483.8	                           1992	          483	
			
491.20-491.21	                   1991	          491.2	
			
493.20	                           1989	          493.90	
493.21	                           1989	          493.91	
			
518.81	                           1987	          799.1	
518.82-518.89	                   1987	          518.8	
			
524.00-524.09	                   1992	          524.0	
524.10-524.19	                   1992	          524.1	
524.60-524.69	                   1991	          524.6	
524.70-524.79	                   1992	          524.8	
			
530.10-530.11, 530.19	           1993	          530.1	
530.18	1993	530.1	
530.82-530.84, 530.89	           1993	          530.8	
			
535.00-535.01	                   1991	          535.0	
535.10-535.11	                   1991	          535.1	
535.20-535.21	                   1991	          535.2	
535.30-535.31	                   1991	          535.3	
535.40-535.41	                   1991	          535.4	
535.50-535.51	                   1991	          535.5	
535.60-535.61	                   1991	          535.6	
			
537.82	                           1990	          537.89	
537.83	                           1991	          537.82	
			
562.02	                           1991	          562.00	
562.03	                           1991	          562.01	
562.12	                           1991	          562.10	
562.13	                           1991	          562.11	
			
569.84	                           1990	          557.1	
569.85	                           1991           569.84	
			
596.51-596.53	                   1992	          596.5	
596.54 	                           1992	          344.61	
596.55-596.59	                   1992	          596.5	
			
599.81-599.89	                   1992	          599.8	
			
645.0	                           1991	          645	
			
651.30-651.31,651.33	           1989	          651.00-651.01,651.03	
651.40-651.41,651.43	           1989	          651.10-651.11,651.13	
651.50-651.51,651.53	           1989	          651.20-651.21,651.23	
651.60-651.61,651.63 	           1989	          651.80-651.81,651.83	
			
654.20-654.21,654.23	           1990	          654.2,654.9	
654.90-651.94	                   1990	          654.2,654.9	
			
657.0	                           1991	          657	
			
659.60,659.61,659.63	           1992	          659.80,659.81,659.83	
			
665.10,665.11	                   1992	          665.10,665.11,665.12,665.14	
			

Note: The title for the subcategory, 665.1 has been changed,     		
making the fifth-digit subclassification, 665.12 and 665.14 invalid.		

                               Effective		
Current code(s) assignment     October 1       Previous code(s) assignment

670.0	                           1991	          670	
			
672.0	                           1991	          672	
			
692.72-692.74	                   1992	          692.79	
692.82-692.83	                   1992	          692.89	
			
702.0-702.8	                   1991	          702	
			
704.02	                           1993	          704.09	
			
710.5	                           1992	          288.3,729.1	
			
733.10-733.16, 733.19	           1993	          733.1	
			
738.10-738.19	                   1992	          738.1	
			
747.60-747.64, 747.69	           1993	          747.6	
747.82	1993	747.89	
			
753.10-753.17,753.19	           1990	          753.1	
			
759.81-759.89	                   1989	          759.8	
			
760.75	                           1991	          760.79	
			
764.00-764.09	                   1988	          764.0	
764.10-764.19	                   1988	          764.1	
764.20-764.29	                   1988	          764.2	
764.90-764.99	                   1988	          764.9	
			
765.00-765.09	                   1988	          765.0	
765.10-765.19	                   1988	          765.1	
			
780.01-780.09	                   1992	          780.0	
			
780.03	                           1993	          780.01	
			
780.57	                           1992	          780.51,780.53	
			
788.20-788.21, 788.29	           1993	          788.2	
			
788.30-788.39	                   1992	          788.3	
			
788.41-788.43	                   1993	          788.4	
788.61-788.62, 788.69	           1993	          788.6	
			
790.91	                           1993	          790.9	
790.92	                           1993	          286.9	
790.93, 790.99	                   1993	          790.9	
			
795.8	                           1986	          795.7	
			
864.05	                           1992	          864.09	
864.15	                           1992	          864.19	
			
925.1-925.2	                   1993	          925	
			
995.60-995.69	                   1993	          995.0	
			
996.51-996.59	                   1987	          996.5	
996.60-996.69	                   1989	          996.6	
996.70-996.79	                   1989	          996.7	
996.80-996.89	                   1987	          996.8	
996.85	                           1990	          999.8	
			
V05.3-V05.4	                   1993	          V05.8	
			
V07.4	                           1992	          V07.8	
			
V09.0-V09.91	                   1993	          No previous code assignments	
			
V25.43	                           1992	          V25.49	
V25.5	                           1992	          V25.8	
			
V29.0-V29.8	                   1992	          V71.8	
V29.9	                           1992	          V71.9	
			
V30.00-V30.01	                   1989	          V30.0	
V31.00-V31.01	                   1989	          V31.0	
V32.00-V32.01	                   1989	          V32.0	
V33.00-V33.01	                   1989	          V33.0	
V34.00-V34.01	                   1989	          V34.0	
V35.00-V35.01	                   1989	          V35.0	
V36.00-V36.01	                   1989	          V36.0	
V37.00-V37.01	                   1989	          V37.0	
V39.00-V39.0l	                   1989	          V39.0	
			
V72.81-V72.85	                   1993	          V72.8	
V73.88-V73.89	                   1993	          V73.8	
V73.98-V73.99	                   1993	          V73.9	

1/ Before October 1986 contents of current code 36.05 would have been assigned 
   to 36.0.
2/ Codes 78.90-78.99 were retitled as "Insertion of bone growth stimulator" in 
   October 1987; the previous contents of codes 78.90-78.99 were reassigned to 
   codes 78.40-78.49.
3/ Codes 99.71-99.79 were deleted in October 1987; their contents were not 
   transferred elsewhere. In the October 1988 revision, codes 99.71-99.79 were 
   reclassified as "Therapeutic apheresis."

 

APPENDIX C
Civilian Population* by Sex, Age, Geographic Region and Race United States, July 1, 1994
   [Population estimates consistent with Series P-25,
    Current Population Reports, U.S. Bureau of the Census]


Age, geographic		
region and race      Both sexes      Male       Female
	
	                 Population in thousands
			
All ages              258,932      125,836      133,096
			
   Northeast           51,310       24,697       26,622
   Midwest	       61,290       29,777       31,513
   South	       89,918       43,391       46,527
   West	               56,405       27,970       28,435
			
   White	      215,375      105,157      110,217
   Black	       32,405       15,274       17,131
   All other	       11,152        5,404        5,747
			
Under 15 years	       57,338       29,354       27,985
			
   Under 1 year	        3,870        1,981        1,889
   1-4 years	       15,857        8,114        7,743
   5-14 years	       37,611       19,260       18,352
			
   Northeast	       10,593        5,425        5,168
   Midwest	       13,513        6,921        6,592
   South	       19,830       10,142        9,689
   West	               13,402        6,866        6,536
			
   White  	       45,510       23,351       22,159
   Black	        8,921        4,523        4,398
   All other	        2,908        1,480        1,428
			
15-44 years	      117,585       58,467       59,118
			
   15-24 years	       35,397       17,872       17,525
   25-34 years	       40,811       20,199       20,612
   35-44 years	       41,377       20,396       20,981
			
   Northeast	       23,066       11,430       11,635
   Midwest	       27,634       13,757       13,877
   South	       40,671       19,998       20,673
   West	               26,214       13,281       12,933
			
   White	       96,334       48,325       48,009
   Black	       15,634        7,412        8,223
   All other	        5,616        2,730        2,886
			
45-64 years			
	               50,850       24,540       26,311
   45-54 years       
   55-64 years         29,834       14,557       15,277
                       21,016        9,982       11,034
	               
   Northeast			
   Midwest	       10,422        4,977        5,446
   South	       12,035        5,833        6,202
   West	               17,887        8,570        9,317
	               10,506        5,160        5,346
   White			
   Black	       43,780       21,352       22,428
   All other	        5,170        2,303        2,867
	                1,901          885        1,015
65 years & over	       33,158       13,475       19,683
			
   65-74 years	       18,712        8,290       10,422
   75-84 years 	       10,925        4,206        6,719
   85 years and over	3,522          980        2,542
			
   Northeast	        7,238        2,865        4,373
   Midwest	        8,107        3,266        4,841
   South	       11,530        4,681        6,849
   West	                6,283        2,663        3,620
			
   White               29,751       12,130       17,621
   Black                2,680        1,036        1,644
   All other              727          309          419


*The NSAS used the civilian noninstitutional population to calculate hospital utilization rates from 1965 through 1980. 
Beginning in 1981, the civilian resident population has been used to calculate rates.  If you have purchased NSAS tapes for
years before 1981 and calculated rates using the civilian noninstitutionalized population provided in the documentation,
these rates will have to be adjusted to be comparable to 1994 rates using the civilian resident population.
Civilian Population of the United States, July 1, 1994. Estimates by Age, Sex, and Region
Data are consistent with the estimates announced in Census Advisory CB94-43.  Methodology is described in 
Current Population Report Series P25-1106.  Release date 3/15/94


                        
     United States             Northeast              Midwest                 South                  West
Age   Total    Male    Female   Total  Male   Female   Total  Male   Female  Total  Male   Female  Total  Male   Female                                                                                                                  
_________________________________________________________________________________________________________________________
                     Civilian Population in Thousands
_________________________________________________________________________________________________________________________
All   258,932  125,836 133,096  51,319 24,697 26,622   61,290 29,777 31,513  89,918 43,391 46,527  56,405 27,970 28,435                                                                                              
0-14   57,338  29,354  27,985   10,593  5,425  5,168   13,513  6,921  6,592  19,830 10,142  9,689  13,402  6,866  6,536
0-4    19,727  10,094   9,633    3,681  1,885  1,796    4,444  2,274  2,170   6,786  3,471  3,316   4,816  2,465  2,351
5-9    18,859  9,657    9,201    3,533  1,812  1,722    4,471  2,291  2,180   6,494  3,320  3,174   4,360  2,234  2,126
10-14  18,753  9,602    9,150    3,379  1,729  1,650    4,598  2,356  2,242   6,550  3,351  3,199   4,226  2,167  2,059                                                                                              
15-44 117,585 58,467   59,118   23,066 11,430 11,635  27,634  13,757 13,877  40,671 19,998 20,673  26,214 13,281 12,933
15-19  17,517  8,951    8,566    3,189  1,624  1,565   4,294   2,194  2,101   6,216  3,162  3,054   3,817  1,972  1,846
20-24  17,880  8,921    8,959    3,433  1,712  1,722   4,235   2,112  2,123   6,340  3,109  3,232   3,871  1,989  1,882
25-29  18,881  9,360    9,521    3,800  1,882  1,918   4,281   2,116  2,165   6,480  3,167  3,314   4,319  2,195  2,124
30-34  21,930 10,838   11,091    4,394  2,169  2,225   5,048   2,495  2,553   7,504  3,665  3,839   4,984  2,509  2,475
35-39  21,771 10,750   11,020    4,355  2,146  2,208   5,135   2,549  2,586   7,415  3,616  3,799   4,865  2,439  2,427
40-44  19,606  9,645    9,961    3,895  1,897  1,997   4,640   2,291  2,349   6,715  3,280  3,435   4,357  2,177  2,180                                                                                              
45-64  50,850 24,540   26,311   10,422  4,977  5,446  12,035   5,833  6,202  17,887  8,570  9,317  10,506  5,160  5,346
45-49  16,649  8,152    8,496    3,374  1,630  1,744   3,875   1,901  1,975   5,795  2,827  2,968   3,605  1,795  1,810
50-54  13,186  6,405    6,781    2,701  1,297  1,405   3,114   1,515  1,599   4,625  2,233  2,392   2,745  1,360  1,386
55-59  10,935  5,243    5,692    2,233  1,062  1,171   2,625   1,264  1,361   3,879  1,843  2,036   2,197  1,074  1,123
60-64  10,082  4,739    5,342    2,114    988  1,126   2,421   1,153  1,268   3,588  1,667  1,921   1,959    932  1,027                                                                                              
65+    33,158 13,475   19,683    7,238  2,865  4,373   8,107   3,266  4,841  11,530  4,681  6,849   6,283  2,663  3,620
65-69   9,970  4,500    5,471    2,150    958  1,191   2,383   1,088  1,296   3,531  1,583  1,948   1,907    871  1,035
70-74   8,741  3,790    4,951    1,887    801  1,087   2,073     897  1,176   3,083  1,331  1,752   1,698    761    937
75-79   6,574  2,655    3,919    1,456    569    886   1,625     647    977   2,248    907  1,342   1,245    532    713
80-84   4,351  1,550    2,801      955    328    627   1,092     382    709   1,500    532    969     804    308    496
85+     3,522    980    2,542      790    209    582     935     251    683   1,167    329    838     629    191    439
Civilian Population of the United States, July 1, 1994.  Estimates by Age, Sex, and Race    
(Consistent with the 1990 Census, as enumerated.)
 

      All races                 White                    Black                  Other races
Age   Total   Male    Female    Total    Male    Female  Total   Male   Female  Total  Male  Female
______________________________________________________________________________________________________________                        
                         Civilian Population in Thousands  
______________________________________________________________________________________________________________
Total 258,932 125,836 133,096   215,375 105,157 110,217  32,405 15,274  17,131  11,152 5,404 5,747                                                             
0-4    19,727  10,094   9,633    15,592   7,995   7,597   3,119  1,581   1,538   1,017   519   498
0       3,870   1,981   1,889     3,041   1,560   1,481     619    314     305     210   107   103
1       3,878   1,985   1,893     3,060   1,569   1,491     616    313     303     202   103    99
2       3,956   2,023   1,933     3,132   1,604   1,528     619    314     305     205   105   100
3       3,990   2,041   1,949     3,163   1,622   1,541     623    315     308     204   104   100
4       4,032   2,064   1,968     3,195   1,640   1,556     642    325     317     195   100    95                                                             
5-9    18,859   9,657   9,201    14,997   7,695   7,302   2,939  1,491   1,448     923   471  452
5       3,884   1,989   1,894     3,063   1,572   1,491     630    319     311     190    98   93
6       3,792   1,940   1,852     3,011   1,544   1,468     595    302     293     186    95   91
7       3,747   1,917   1,830     2,985   1,531   1,454     582    294     287     180    92   88
8       3,595   1,841   1,754     2,874   1,475   1,399     544    276     268     177    90   87
9       3,841   1,969   1,872     3,063   1,574   1,490     588    299     289     189    96   93                                                             
10-14  18,753   9,602   9,150    14,921    7,661  7,260   2,864  1,452   1,412     968   490  478
10      3,744   1,920   1,824     2,984    1,535  1,450     567    288     279     192    98   95
11      3,770   1,931   1,840     3,010    1,545  1,465     566    287     279     194    99   96
12      3,768   1,927   1,841     2,994    1,535  1,459     580    294     286     195    98   97
13      3,722   1,903   1,818     2,962    1,519  1,443     562    285     278     197    99   98
14      3,748   1,921   1,828     2,971    1,526  1,444     588    298     289     190    96   94                                                             
15-19  17,517   8,951   8,566    13,955    7,152  6,803   2,717  1,372   1,345     845   428  417
15      3,602   1,848   1,754     2,849    1,466  1,383     572    291     281     181    92   89
16      3,515   1,808   1,707     2,802    1,444  1,357     544    277     267     169    86   83
17      3,561   1,834   1,726     2,836    1,465  1,371     555    283     272     170    87   83
18      3,324   1,692   1,631     2,657    1,357  1,300     510    256     254     157    79   78
19      3,515   1,769   1,746     2,811    1,420  1,392     536    265     271     168    84   84                                                             
20-24  17,880   8,921   8,959    14,369    7,212  7,157   2,587  1,248   1,339     924   461  463
20      3,389   1,697   1,692     2,708    1,362  1,346     513    252     262     168    84   84
21      3,397   1,698   1,699     2,703    1,357  1,345     516    252     264     178    89   89
22      3,509   1,751   1,759     2,815    1,413  1,402     510    246     264     184    92   92
23      3,750   1,865   1,885     3,024    1,514  1,510     531    253     278     195    98   97
24      3,834   1,910   1,924     3,118    1,566  1,553     517    245     272     199    99  100                                                             
25-29  18,881   9,360   9,521    15,368    7,693  7,675   2,558  1,201   1,357     956   466  489
25      3,689   1,837   1,853     3,009    1,511  1,498     488    230     257     192    95   97
26      3,619   1,792   1,826     2,937    1,469  1,468     495    232     262     187    91   95
27      3,721   1,844   1,877     3,032    1,518  1,514     501    235     266     187    91   96
28      3,618   1,788   1,830     2,948    1,471  1,477     491    230     261     179    87   92
29      4,234   2,099   2,136     3,442    1,724  1,718     582    273     310     210   102  108                                                             
30-34  21,930  10,838  11,091    18,104    9,047  9,056   2,786  1,288   1,497   1,040   503  537
30      4,301   2,126   2,175     3,532    1,765  1,767     562    261     301     207   100  106
31      4,281   2,115   2,166     3,524    1,759  1,765     547    254     293     210   101  109
32      4,382   2,165   2,217     3,625    1,811  1,814     553    255     297     204    99  105
33      4,385   2,158   2,227     3,640    1,813  1,827     540    247     293     205    98  107
34      4,581   2,275   2,306     3,782    1,900  1,882     585    271     313     214   104  111                                                             
                        Civilian population in thousands
35-39  21,771  10,750  11,020    18,093    9,035  9,059   2,695  1,247   1,448     983   469  514
35      4,480   2,215   2,265     3,711    1,855  1,856     562    261     302     207   100  107
36      4,397   2,170   2,227     3,664    1,828  1,836     537    248     289     196    94  102
37      4,432   2,188   2,244     3,683    1,838  1,845     552    255     297     197    94  103
38      4,019   1,975   2,044     3,348    1,665  1,683     489    225     264     182    85   96
39      4,442   2,202   2,240     3,687    1,848  1,839     554    258     296     200    95  105                                                             
40-44  19,606   9,645   9,961    16,445    8,186  8,259   2,292  1,056   1,237     869   404  465
40      4,197   2,067   2,130     3,508    1,747  1,761     502    232     270     187    88   99
41      3,991   1,960   2,031     3,349    1,664  1,685     460    210     249     182    85   97
42      3,904   1,920   1,984     3,289    1,637  1,652     449    206     243     167    78   89
43      3,702   1,812   1,890     3,091    1,533  1,559     436    199     236     175    81   94
44      3,813   1,887   1,926     3,208    1,605  1,602     446    208     238     159    73   86                                                             
45-49  16,649   8,152   8,496    14,222    7,039  7,183   1,737    791     946     690   322  367
45      3,650   1,793   1,857     3,088    1,534  1,554     406    187     219     156    72   84
46      3,542   1,736   1,806     3,030    1,502  1,528     368    167     200     145    67   78
47      3,836   1,880   1,956     3,316    1,642  1,674     374    170     204     146    68   78
48      2,648   1,289   1,360     2,266    1,114  1,151     266    119     147     116    55   62
49      2,972   1,455   1,517     2,523    1,247  1,275     322    147     175     127    60   66                                                             
50-54  13,186   6,405   6,781    11,350    5,568  5,782   1,339    602     738     497   236  261
50      2,888   1,407   1,481     2,482    1,221  1,261     293    132     161     113    54   59
51      2,930   1,428   1,501     2,548    1,253  1,294     278    126     152     104    49   55
52      2,548   1,237   1,312     2,190    1,074  1,116     263    118     145      95    45   50
53      2,440   1,182   1,258     2,098    1,026  1,072     250    111     138      92    44   48
54      2,380   1,151   1,229     2,032      993  1,039     256    114     141      92    44   49                                                             
55-59  10,935   5,243   5,692     9,435    4,573  4,863   1,110    487     623     389   183  206
55      2,283   1,098   1,184     1,950      947  1,003     246    110     136      87    41   45
56      2,280   1,095   1,185     1,966      955  1,011     234    102     133      80    38   42
57      2,178   1,043   1,134     1,876      908    968     224     98     126      78    37   41
58      2,021     966   1,055     1,758      849    909     195     85     110      69    32   37
59      2,173   1,041   1,132     1,886      914    972     212     92     119      75    35   40                                                             
60-64  10,082   4,739   5,342     8,772    4,172  4,601     984    424     560     325   144  181
60      1,981     934   1,046     1,714      817    897     198     86     111      69    31   38
61      1,953     923   1,030     1,693      810    883     194     84     110      66    29   36
62      1,965     921   1,044     1,705      809    896     196     84     112      64    28   36
63      2,065     971   1,094     1,810      861    949     192     82     110      63    28   35
64      2,118     990   1,128     1,850      875    975     204     88     116      65    28   37                                                             
65-69   9,970   4,500   5,471     8,792    3,998  4,794     906    386     520     273   116  157
65      2,059     948   1,111     1,796      836    960     202     86     116      61    26   35
66      2,071     948   1,124     1,822      839    983     193     85     108      56    24   33
67      2,003     905   1,098     1,765      805    960     184     77     107      54    23   31
68      1,897     845   1,052     1,678      752    926     168     71      96      52    22   30
69      1,940     854   1,086     1,730      766    965     159     67      92      51    21   29                                                             
70-74   8,741   3,790   4,951     7,840    3,420  4,419     694    279     415     208    91   117
70      1,875     824   1,051     1,674      742    932     153     61      92      48    21    27
71      1,801     786   1,015     1,611      706    904     146     59      86      45    20    25
72      1,811     791   1,020     1,630      716    913     138     56      83      43    19    24
73      1,695     729     966     1,527      661    866     130     52      79      38    16    21
74      1,559     659     899     1,398      594    804     127     51      76      34    14    20                                                             
                        Civilian population in thousands
75-79   6,574   2,655  3,919      5,949    2,414  3,534     499    188     311     126    53    73
75      1,473     614    859      1,326      555    771     117     47      70      30    12    18
76      1,369     563    806      1,243      513    730     101     39      62      25    10    15
77      1,294     524    770      1,173      478    695      96     36      61      25    11    14
78      1,254     496    758      1,139      453    686      92     33      59      24    10    14
79      1,184     459    725      1,068      415    653      94     34      60      23    10    13                                                             
80-84   4,351   1,550  2,801      3,962    1,412  2,550     316    107     210      72    31    41
80      1,048     393    655        953      359    594      77     26      51      18     8    10
81        966     352    614        878      321    557      72     24      47      16     7     9
82        855     306    549        783      279    504      58     20      38      14     6     8
83        784     268    516        716      244    471      55     18      37      13     5     7
84        699     232    467        633      209    424      54     18      36      12     5     7                                                             
85+     3,522     980  2,542      3,209      885  2,324     265     76     188      48    18    30
                                                             
0-14   57,338  29,354 27,985     45,510   23,351 22,159   8,921  4,523   4,398   2,908 1,480 1,428
15-44 117,585  58,467 59,118     96,334   48,325 48,009  15,634  7,412   8,223   5,616 2,730 2,886
45-64  50,850  24,540 26,311     43,780   21,352 22,428   5,170  2,303   2,867   1,901   885 1,015                                                             
15+   201,593  96,482 105,112   169,865   81,807 88,058  23,484 10,750  12,734   8,244 3,924 4,320
45+    84,008  38,015  45,994    73,531   33,482 40,049   7,850  3,339   4,511   2,628 1,194 1,434
65+    33,158  13,475  19,683    29,751   12,130 17,621   2,680  1,036   1,644     727   309   419
75+    14,446   5,185   9,261    13,120    4,712  8,408   1,080    371     709     247   103   144
    
APPENDIX D
UNWEIGHTED FREQUENCIES FOR SELECTED NSAS VARIABLES
 SURVEY                      Cumulative  Cumulative
 YEAR   Frequency   Percent   Frequency    Percent
 --------------------------------------------------
   94     117861     100.0      117861      100.0
 FACILITY                       Cumulative  Cumulative
 TYPE      Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1      71521      60.7       71521       60.7
       2      46340      39.3      117861      100.0
 UNITS FOR                       Cumulative  Cumulative
 AGE        Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
       1      116089      98.5      116089       98.5
       2        1718       1.5      117807      100.0
       3          54       0.0      117861      100.0
 AGE IMPUTATION                 Cumulative  Cumulative
 FLAG      Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1       1056       0.9        1056        0.9
       2     116805      99.1      117861      100.0
                            Cumulative  Cumulative
 SEX   Frequency   Percent   Frequency    Percent
 -------------------------------------------------
   1      50941      43.2       50941       43.2
   2      66920      56.8      117861      100.0
 SEX IMPUTATION                 Cumulative  Cumulative
 FLAG      Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1        715       0.6         715        0.6
       2     117146      99.4      117861      100.0
                              Cumulative  Cumulative
 RACE   Frequency   Percent   Frequency    Percent
 --------------------------------------------------
    1      58374      49.5       58374       49.5
    2       6089       5.2       64463       54.7
    3        261       0.2       64724       54.9
    4       1417       1.2       66141       56.1
    5       1192       1.0       67333       57.1
    9      50528      42.9      117861      100.0
                                  Cumulative  Cumulative
 DISPOSITION Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
        1     106588      90.4      106588       90.4
        2       2772       2.4      109360       92.8
        3       2026       1.7      111386       94.5
        4       1551       1.3      112937       95.8
        5         98       0.1      113035       95.9
        6       1050       0.9      114085       96.8
        9       3776       3.2      117861      100.0
 MONTH OF                       Cumulative  Cumulative
 SURGERY   Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
 01            8957       7.6        8957        7.6
 02            8964       7.6       17921       15.2
 03           10717       9.1       28638       24.3
 04            9938       8.4       38576       32.7
 05           10151       8.6       48727       41.3
 06           10528       8.9       59255       50.3
 07            9277       7.9       68532       58.1
 08           10498       8.9       79030       67.1
 09            9550       8.1       88580       75.2
 10            9780       8.3       98360       83.5
 11            9977       8.5      108337       91.9
 12            9524       8.1      117861      100.0
                               Cumulative  Cumulative
 REGION   Frequency   Percent   Frequency    Percent
 ----------------------------------------------------
      1      23991      20.4       23991       20.4
      2      27126      23.0       51117       43.4
      3      43990      37.3       95107       80.7
      4      22754      19.3      117861      100.0
          
 PRINCIPAL EXPECTED SOURCE       Cumulative  Cumulative
 OF PAYMENT Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00              768       0.7         768        0.7
 01             2862       2.4        3630        3.1
 02            36521      31.0       40151       34.1
 03             8607       7.3       48758       41.4
 04              633       0.5       49391       41.9
 05              846       0.7       50237       42.6
 06            13471      11.4       63708       54.1
 07            13669      11.6       77377       65.7
 08            27891      23.7      105268       89.3
 09             3690       3.1      108958       92.4
 10             1991       1.7      110949       94.1
 99             6912       5.9      117861      100.0
 ADDITIONAL                      Cumulative  Cumulative
 ESOP #1    Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00               14       0.0          14        0.0
 01               30       0.1          44        0.1
 02              806       2.5         850        2.6
 03             3660      11.3        4510       14.0
 04              258       0.8        4768       14.8
 05              425       1.3        5193       16.1
 06             9393      29.1       14586       45.2
 07             1336       4.1       15922       49.3
 08            12979      40.2       28901       89.6
 09             2364       7.3       31265       96.9
 10             1008       3.1       32273      100.0
 Frequency Missing = 85588
 ADDITIONAL                      Cumulative  Cumulative
 ESOP #2    Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00                4       1.1           4        1.1
 01                1       0.3           5        1.4
 03               10       2.8          15        4.2
 04                1       0.3          16        4.4
 05                6       1.7          22        6.1
 06               59      16.4          81       22.5
 07               10       2.8          91       25.3
 08              110      30.6         201       55.8
 09              103      28.6         304       84.4
 10               56      15.6         360      100.0
 Frequency Missing = 117501
WEIGHTED FREQUENCIES FOR SELECTED NSAS VARIABLES
 SURVEY                      Cumulative  Cumulative
 YEAR   Frequency   Percent   Frequency    Percent
 --------------------------------------------------
   94   18849556     100.0    18849556      100.0
 FACILITY                       Cumulative  Cumulative
 TYPE      Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1   15972629      84.7    15972629       84.7
       2    2876927      15.3    18849556      100.0
 UNITS FOR                       Cumulative  Cumulative
 AGE        Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
        1   18652656      99.0    18652656       99.0
        2     189619       1.0    18842275      100.0
        3       7281       0.0    18849556      100.0
 AGE IMPUTATION                Cumulative  Cumulative
 FLAG     Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1     272188       1.4      272188        1.4
       2   18577368      98.6    18849556      100.0
                               Cumulative  Cumulative
 SEX      Frequency   Percent   Frequency    Percent
 ----------------------------------------------------
   1       8178160      43.4     8178160       43.4
   2      10671396      56.6    18849556      100.0
 SEX IMPUTATION                 Cumulative  Cumulative
 FLAG      Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
       1      103341       0.5      103341        0.5
       2    18746215      99.5    18849556      100.0
                              Cumulative  Cumulative
 RACE   Frequency   Percent   Frequency    Percent
 --------------------------------------------------
    1   11409374      60.5    11409374       60.5
    2    1118206       5.9    12527580       66.5
    3      67768       0.4    12595348       66.8
    4     180743       1.0    12776091       67.8
    5     138030       0.7    12914121       68.5
    9    5935435      31.5    18849556      100.0
                                  Cumulative  Cumulative
 DISPOSITION Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
        1    16887324      89.6    16887324       89.6
        2      580532       3.1    17467856       92.7
        3      234252       1.2    17702108       93.9
        4      310740       1.6    18012848       95.6
        5       17498       0.1    18030346       95.7
        6      140717       0.7    18171063       96.4
        9      678493       3.6    18849556      100.0
 MONTH OF                       Cumulative  Cumulative
 SURGERY   Frequency   Percent   Frequency    Percent
 -----------------------------------------------------
 01         1499478       8.0     1499478        8.0
 02         1492826       7.9     2992304       15.9
 03         1754314       9.3     4746618       25.2
 04         1637671       8.7     6384289       33.9
 05         1637262       8.7     8021551       42.6
 06         1698481       9.0     9720032       51.6
 07         1454186       7.7    11174218       59.3
 08         1630010       8.6    12804228       67.9
 09         1483253       7.9    14287481       75.8
 10         1509868       8.0    15797349       83.8
 11         1546426       8.2    17343775       92.0
 12         1505781       8.0    18849556      100.0
                               Cumulative  Cumulative
 REGION   Frequency   Percent   Frequency    Percent
 ----------------------------------------------------
      1    4232868      22.5     4232868       22.5
      2    4896485      26.0     9129353       48.4
      3    6251021      33.2    15380374       81.6
      4    3469182      18.4    18849556      100.0


 PRINCIPAL EXPECTED SOURCE       Cumulative  Cumulative
 OF PAYMENT Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00            69740       0.4       69740        0.4
 01           449207       2.4      518947        2.8
 02          5690802      30.2     6209749       32.9
 03          1245640       6.6     7455389       39.6
 04            92071       0.5     7547460       40.0
 05           135824       0.7     7683284       40.8
 06          2435412      12.9    10118696       53.7
 07          2620924      13.9    12739620       67.6
 08          4209070      22.3    16948690       89.9
 09           492910       2.6    17441600       92.5
 10           399418       2.1    17841018       94.6
 99          1008538       5.4    18849556      100.0
 ADDITONAL                       Cumulative  Cumulative
 ESOP #1    Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00             1555       0.0        1555        0.0
 01             6705       0.1        8260        0.2
 02           127199       2.6      135459        2.8
 03           535074      11.0      670533       13.8
 04            37661       0.8      708194       14.6
 05            61531       1.3      769725       15.8
 06          1519805      31.3     2289530       47.1
 07           236322       4.9     2525852       52.0
 08          1813413      37.3     4339265       89.3
 09           356499       7.3     4695764       96.6
 10           164278       3.4     4860042      100.0
 Frequency Missing = 13989514
 ADDITONAL                       Cumulative  Cumulative
 ESOP #2    Frequency   Percent   Frequency    Percent
 ------------------------------------------------------
 00             1214       1.6        1214        1.6
 01                9       0.0        1223        1.6
 03              623       0.8        1846        2.4
 04               81       0.1        1927        2.5
 05              118       0.2        2045        2.7
 06            13346      17.6       15391       20.3
 07             1475       1.9       16866       22.3
 08            16405      21.7       33271       44.0
 09            11834      15.6       45105       59.6
 10            30537      40.4       75642      100.0
 Frequency Missing = 18773914




This page last reviewed: Thursday, January 28, 2016
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