FROM VITAL & HEALTH STATISTICS OF THE NATIONAL CENTER FOR HEALTH STATISTICS 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE � Public Health Service I Nutier 37 ~ Awust 29,1978 

Office Visits to Dermatologists: National Ambulatory 

Medical Care Survey, United States, 1975-76’ 

— 

‘Ge 

This report presents data on office visits to 

dermatologists practicing in the coterminous 

United States. The data presented were colIected 

during 1975 and 1976 by means of the National 

Ambulatory MedicaI Care Survey (NAMCS), a 

continuous survey designed to explore the provision and utilization of ambulatory medical 

care in physicians’ offices and conducted by the 

National Center for Health Statistics. The survey 

sample of physicians was selected from nonfederally employed doctors of medicine and 

osteopathy who are primarily engaged in officebased patient-care practice. It excludes physicians practicing in Alaska and Hawaii and 

physicians whose specialty is anesthesiology, 

pathoIogy, or radiology. 

The estimates are based on information 

obtained from the “Patient Record” (figure 1), 

an encounter form used by participating physicians to record selected information about their 

office visits. A brief description of the sample 

design and an explanation of sampling errors 

associated with the estimates may be found in 

the “Technical Notes” of this report. A more detailed description of the sample design used in 

NAMCS has been presented in an earlier report.z 

1This report was prepared by Trena Ezzati, Division 

of Health Resources Utilization Statistics. 

2National Center for Health Statistics: The Nationsl 

Ambulatory Medicd Care Survey: 1975 summary, 

United States, Januaq/-December 1975, by H. Koch and 

T. McLemore. Vital and Health Statistics. Series 13-No. 

33. DHEW Pub. No. (PHS) 78-1784. Public Health ServDATA HIGHLIGHTS 

During the 24-month period of January 

1975 through December 1976 an estimated 35.7 

million visits were made to office-based physicians specializing in dermatology (table 1). This 

represents 3.1 percent of the estimated 1.2 

billion ambulatory visits to physicians’ offices 

during this period. 

Of the estimated 35.7 million visits to 

dermatologists from January 1975 through 

December 1976, approximately two-thirds (67 

percent) were made to physicians engaged in 

solo practice (table 2). This exceeded the proportion of visits made to aII physicians in solo 

practice (60 percent). Table 2 also shows that 

visits to dermatologists Iocated in metropolitan 

areas (86 percent) exceeded the proportion to 

those practicing in nonmetropolitan areas (14 

percent). 

The data in table 3 show that the proportion 

of visits to dermatologists made by females (60 

percent) exceeded the proportion made by 

males (40 percent). This distribution by sex is 

the same for visits to all office-based physicians. 

The distribution of visits to dermatologists 

(tabIe 3) by age of patient shows that approximately 40 percent of the visits were made by 

persons under 25 years of age. The visit rate per 

100 persons per year varied from a low of 3.6 

for persons under 15 years to a high of 13.7 for 

persons aged 15-24 years. It maybe noted from 

table 3 that the proportion of visits by black 

persons to dermatologists (5 percent) was Iess 

than the proportion made by black persons to 

all physicians (8 percent). 

Oti ice. Washington. U.S. Government Printing Office, Jan. 

~D 1978 . 

-. 
2


Figure 1. PATlENT RECORD 

I ASSURANCE OF CONFIDENTIALITY—AII ,nk,rnmmn wtmh would pwmt odenttfotmnof.. mdwd.al, 

, IWCWe, or an e’t?.bhshmentwall& held,onl,de”tml. ‘+,11be used.3”1”by P:SO”$ engaged,“ and k+ B~~ 

Thec..rpaws of the wwy and vJ#llnot k dndowd or released m omev pc.rmms M used ‘M a.y otherpurpose. 

1. DATE OF VISIT PATIENT RECORD 

NATIONAL AMBULATORY MEDICAL CARE SURVEY .~ 

2. OATE OF BIRTII 4. COLOR OR 5. PATIENT’S PRINCIPAL PROBLEM(S) 6. HEINOUSNESS OF 7. HAVE YOU EVER SEEN RACE COMPLAINT(S), OR SYMPTOM(S) ~ VISIT PFIOBLEM IN ITEM 5a THIS PATlENT 8EFOEIE? 

(/. patunt’s m+’. words) 

I � WHITE 

+ — 

3.	 SEX ~ Cl NEGROI a MOST BLACK IMPORTANT 

~ D FEMALE , 0 OTHER 

~ n MALE D UNKNOWN I b OTHER 

8. MAJOR tlEASONIS) FOR THIS VISIT (Clerk,// map, mamm) 

U ACUTE PROBLEM ,, : WELL AD ULTIC HILO EXAM 

w � ACUTE PROBLEM. FOLLOW-UP ~ ,7 FAMII.Y PLANNING 

“1 � CHRONIC PROEILEM, ROUTINE Z COUNSELING,’ADVICE 

. . U CHRONIC PROBLEM, FLARE. uP ‘ r IMMUNIZATION 

,, � PRENATAL CARE ~ REFERH:O BY OTHER PHYSIAGENCY 

, IJ POSTNATAL CARE O ADMINISTRATIVE PURPOSE 

. � POSTOPERATIVE CARE . L OTHEH (.s~ecdfl 

1 

( Operatwe procedure) 

10. DIAGNOSTIC/TtlERAPEUTIC SERVICES OFSOEREO/PROVIOEO THIS VISIT /C/wck#/ th,t wpfy) 

01 � NONE


02 � LIMITED H1STOF4YIE
 XAM 

03 � GENERAL HISTORVIEXAM 

04 D CLINIC4L LAB. TEST 

05 a BLOOD PRESSURE CHECK 

06 � EKG 

07 n HEARING TEST 

08 � VISION TEST 

09 � EN DESCOPY 

10 D OFFICE SURGERY 

‘R A.34-3 

EV. 8-74 

II •l DRw3 preSCribed


12 � X.FIAY


13 •1 lNJECTIDN


14 D lMMUNIZATlON/DESENSITIZATION


15 @ PHYSIOTKE RAW


16 � MEDICAL COUNSELING


17 � PSYCHDTHEPAPYITHE RAPEUTIC


LISTENING 

la fi OTHER (SPW,IV) 

(Check one) 

~ 0 YES ICINO I ~ VERY SERIOUS I 

I L SERIOUS // YES, {or the problem 

mdmated m / TEM 5a ? I ~ SLIGHTLY SERIOUS 

~ 3 NOT SERIOUS I o YES ~ONO 

9.	 PHYSICIAN’S PRINCIPAL OIAGNOSIS ~ VISIT 

. DIAGNOSIS ASSOCIATE WITH ITEM 58 ENTRY 

b OTHER SIGNIFICANT CURRENT OIAGNOSES 

(In order of mportance) 

11. DISPOSITION THIS VISIT 12. OURATION OF 

(Check all that apply)	 ~ VISIT ( Tim 

actually spent with 

physician) 

C NO FOLLOW UP PLANNEO 

‘ :] RETURN AT SPECIFIEO TIME 

, G RETuRN IF NE EOED. PRN 

4 G TELEPHONE FOLLOW-UP PLANNED 

~ 0 RLFERREO TO OTHER .MINuTES 

PHYSIC IA NIAGENCY 

., :- RkTURNEOTO REFk RRING 

PHYSICIAN 

~ L, AOMIT TO HO SPlrAL 

s i OTHER (@c!fYI_ 

I I 

OEPARTMENT 06 HEa LTH, EDUCATION ANO WELFARE 0.M.0. #6 S.S72106 PU8LIC HEALTH SERVICE EXpIRAT80N OATE 12{3vT5 HEALTH RESOURCES ADMINISTRATION 

NATIONAL CENTER FOR HEALTH 57 AT15TICS 

Data concerning the patient’s prior visit 

status (table 3) show that 74 percent of the 

visits to dermatologists were made by old returning patients and 26 percent by new patients. 

Furthermore, the percent of visits by new 

patients to dermatologists (26 percent) was proportionately higher than such visits to all physicians (15 percent). 

Table 4 presents the most common patient 

problems, complaints, or symptoms presented to 

the dermatologist. The patients’ problems, complaints, or symptoms are coded according to a 

special classification developed for use in 

NAMCS.3 The nine problems, complaints, or 

symptoms presented in table 4 accounted for 84 

percent of all problems presented to the dermatologist. Visits for acne (24 percent) out3National Center for Health Statistics: The National 

Ambulatory Medical Care Survey: symptom classification, United States, by S. Meads and T. McLemore. 

Vital and Health Statistics. Series 2-No. 63. DHEW Pub. 

No. (HRA) 74-1337. Health Resources Administration. 

Washington. U.S. Government Printing Office, May 

1974. 
admcdaa3 

numbered visits to the dermatologist for any 

other problem. 

Information on the physician’s judgment of 

the seriousness of the patient’s problem, complaint, or symptom (in terms of the extent of 

impairment that might result if care were not 

available) is presented in table 5. Compared with 

visits to aIl physicians, the percent of visits to 

dermatologists for “not serious” problems was 

proportionately higher (55 percent compared 

with 49 percent), and the percent for “serious or 

very serious” was proportionately lower ( 12 percent compared with 19 percent). 

Tables 6 and 7 present information on the 

principal diagnosis associated with office visits 

to dermatologists. In table 6 the diagnostic data 

are grouped by the classes used in the Eighth 

Revision International Classification of Diseases, 

Adapted for Use in the United States (ICDA).4 

As might be predicted, the majority (63 percent) 

of diagnoses rendered by the dermatologist fell 

into the category of diseases of the skin and 

subcutaneous tissue. An additional 17 percent of 

the visits were for infective and parasitic diseases. Table 7 provides a listing of the 11 

specific diagnoses most commonly rendered by 

the dermatologist. These 11 diagnoses accounted 

4National Center for Health Statistics: Eighth Rem“sion In terrrational Classification of Diseases, Adapted 

for Use in the United States. PHS Pub. No. 1693. Public 

Health Service. Washington. U.S. Government Printing 

Office, 1967. 

Table 1.	 Nutier and percent distribution of office visits by 

Dhvsician . soaeialtv: United 8tates. 1975-76

Number of 

Physician specialty visits Percent 

I thousands istribution 

All specialities .. .... .. .. .. .. . .. .. . ... . ... 1,155,900 100.0 

General and family practice .. ... .... .. .. 460,287 39.8 

Internal medicine .. ..... . . .... .. .. .. . ... .. .. .. 130,367 11.3 

Pediatrics .. .. .. .. .. ....”.... .. .... . .. .. . .. ... . .. . 107j385 9.3 

Obstetrics and gynecology .. .. .. .. . . .. .. . 97,070 a4 

Generai surgery .. .. ... .... . ... .. .... . . .. .. .. .. . 77,259 6.7 

~ Orthopedic surgery .. .. ... ... .. .. .. .. .. .. .. .. 47,152 4.1 

‘ Dermatology .. ... . .. ....”.. . .. . ... .. .. .. .. .. .. 35,721 3.1 

Ail other .... .. .. .. .. .. .... . .. ... .. .. .. . . .. .. .. .. .. 200,849 17.4 

for approximately 72 percent of all diagnoses 

rendered by the dermatologist. 

Information in table 8 shows that the most 

frequent diagnostic service ordered or provided 

by the dermatologist was the limited examination (48 percent). This percentage did not differ 

statistically from the corresponding statistic for 

all physicians (52 percent). The two therapeutic 

services most frequently ordered or provided by 

the dermatologist were drugs prescribed (55 percent) and office surgery (31 percent). The percentages for these two services were both higher 

than the overall percentages for all physicians 

(44 and 7 percent, respectively). 

Data on disposition (table 8) show that less 

than 1 in 10 (9 percent) of the visits required no 

followup and that approximately two-thirds of 

the visits were scheduled for followup. 

Duration of the visit represents the amount 

of time spent by the patient in face-to-face contact with the physician. From table 8 it may be 

noted that over one-half (58 percent) of the 

visits to dermatologists took less than 11 minutes. The mean duration of visits for office visits 

to dermatologists was approximately 12 minutes. This was significantly less than the estimated mean duration of 15 minutes for all 

physicians. 

Table 2. Nutier and parcent distribution of office visits to 

dermatologists and pareent distribution of office visits to aii 

specialists by type and location of physician’s practice: 

United 6tates, 1975-76 

Type and location of Visits to Visits to all 

physician’s practice dermatologists specialists 

Number Percent distribution 

in thousends 

Aii visits ........... .... 35,721 100.0 100.0 

Type of practice 

8010 .... .... .... .... .. .. .... . 23,902 66.9 W.o 

Partner ... .... ..... . ... .. ... 3,168 8.9 17.1 

Group .... .. .. .. .... ....”.. 8,630 24.2 22.9 

Location of practice 

Metropolitan ... .. .. .. .. . 30,588 85.6 73.3 

Nonmetropolitan .. ... 5,133 14.4 26.7 
.

—. 

4 aduancedata 

*, 

I 

Table 3. Number, percent distribution, and rate trer vear of office visits to dermatolocrists and Dercent distribution of office visits to all — 

specialtiats”by Detien;’s age, sex, race, and Drier visit status:- Unitad States, 1975-76 

Visits to dermatologists 

Patient characteristic 

All visits ........ ...................... ............ ........ ........ 

Age

— 

Under 15 years ................................. ..................... 

15-24 years ............................. ............................... 

2544 years ............... ............................................. 

45-64 years ................................................. ........... 

65 years and over ...... ...................... ...................... 

— 

Sex

Female ... ........ .. .......................................... ........... 

Male .............. ...... ........ .......................................... 

Race 

White ................ ................ ............ ......................... 

Black ..... .......... ...... .. .............. ................................ 

Other ..................... .................... .............. .............. 

Prior visit status 

New patient .............. ...... .. ...... ............................ ... 

Old patient: 

New problem ... .................... .. ............................ 

Old problem ............................. ........................ . 

Number 

in thousands 

35,721 

3,792 

10,583 

8,954 

7,881 

4,511 

21,369 

14,352 

33,576 

1,813 

*332 

9,228 

4,214 

22,279 

Number per Percent 100 persons distribution per yaar 

100.0 8.6 

10.6 3.6 

29.6 13.7 

25.1 8.5 

22.1 9.2 

12.6 10.5 

58.8 9.9 

40.2 7.1 

94.0 9.3 

5.1 3.9 

0.9 1 

26.8 

Visits to all 

specialists 

Percent 

distribution 

100.0 

18.1 

15.1 

25.5 

25.1 

16.2 

60.4 

39.6 

89.9 

7.8 

2.3 _ 

14.6 

23.2 

62.3 

Table 4. Nu rnber, percent, and cu mu Iativa percent of office visits to dermatologists by t he 9 most common patient Droblems, comdaints. . . 

or symptoms: United States, 1975-76 

9 most common patient Number of Percent Cumulative 

Rank problams, complaints, or symptoms visits in of percent of 

and NAMCS codesl thousands visits2 visits 

1 Acne .. .. .... ... . .... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .... .... .. .. ....lOO 8,431 23.6 23.6 

2 Allergic skin reactions ,., .. ..... . ... ... .. . ... .. .. .... ...1 12 5,712 16.0 39.6 

3 Other specific symptoms referable 

to sKn .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... ... ..... . .. ....l2O 3,930 11.0 50.6 

4 Swelling or mass of skin .. .... .. .. ... .. ... .. .... .. .....1 15 3,497 9.8 60.4 

5 Warts ... .. .... .. .. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .. .... .. .. .. .. .. . 111 3,002 8.4 68.8 

6 Skin irritations not elsewhere classified...l ....l 13 2,118 5.9 74.7 

7 Discoloration or pigmentation ...$.’... .. .. .. ... ....l 04 1,871 5.2 79.9 

8 Skin moles ... .. .. .. .. .. .... ... ..... .. .. .. ... . ... ... .. ... . .. ..l (J9 818 2.3 82.2 

9 Surgical aftercare .. .. .. .. .. .. .. .. .. .. .. .. .. .. . ... .. .. .... .986 640 1.8 84.0 

#- 1 Symptom titles and code numbers are based on a symptom classitlcation developed for use in NAM(X. 2Based on an estimated 35,721,000 tilts. 

-
5


Table 5. Number and percent distribution of office visits to


dermatologists and percent distribution of office visits toall


speciaIiats by degree of seriousness of pat ient’s prob [em:


United States, 1975-76


Visits to all 

Degree of seriousness Visits to dermatologists specialists 

All visits.................. 

= 

Serious or very serious 4,152 11.6 19.2 

Slightly serious ........... 11,869 33.2 32.3 

Not serious ................. 19,701 55.2 48.5 

NOTE: Numbers may not add to totals due to rounding. 

Table 6. Number and percent distribution of offie visits to 

dermatolocsists by major ICDA diagnostic grows: United 

States, 19%76 -

Major I CDA diagnostic group 

and ICDA codel 

Infective and parasitic 

diseases................................000-136


Neoplasms .............................140-239


Diseasesof the respiratory


system .................................480-519


Diseasesof the skin and subcutaneous


tissue ...................................680-709


Symptoms and illdefined


conditions ............................78 O-796


All other diagnoses .............................


lD~gno~i~ ~oup$ and codes are 

Number ‘ercent 

of visits of 

in thousands visits 

35,721 100.0 

5,888 16.5 

3*743 10.5 

*553 1.6 

22,546 63.1 

’568 1.6 

2,415 6.8 

baaad on E&hth Revision 

Intematkmal C7assi~icationof Diwimw, Adapted for Use in the 

United States. 

oTable 7. Nuder, percent, and cumulative percent 

11 most common prinicpal 

Rank diagnoses and ICDA 

of office visits to’ dermatologists by 11 most common principal diagnoses: 

1


2


3


4


5


6


7


8


9


10


11


codesl 

Diseasesof sebaceousglands ......................706


Other eczema and dermatitis., ....................692


Other viral diseases.....................................079


Other hypertrophic and atrophic


conditions of skin ..................................701


Other malignant neoplasm .........................1 73


Psoriasisand similar disorders ....................696


Benign neoplasm of skin ............................216


Pruitus and related conditions ....................698


Dermatophytosis ........................................110


Saborrheic dermatitis .................................69O


Other diseasesof skin.................................7O9


Unitad States, 1975-76


Number Percent 

of visits of 

in thousands visits2 

9,598 26.9 

3,701 10.4 

3,088 8.7 

1,965 5.5 

1,737 4.9 

1,372 3.8 

1,188 3.4 

820 2.3 

782 2.2 

743 2.1 

727 2.0 

Cumulative 

percent of 

visits 

26.9 

37.3 

46.0 

51.5 

56.4 

60.2 

63.6 

65.9 

68.1 

70.2 

72.2 

J 

lDiagnostic ~tegories and codes are based on Eighth Revision Interrrafi-orsd C%Stykatbn ofD~ww% Adwtedfor u= in the 

Uni ed State& i 8ased on an estimated 35,721,000 visits. 
----------------------------- ---

----------------------

6 

Table 8. Number end percent of office visits to dar~tologi~s and percent of office visits to all specialists by services ordered or 

provided, end disposition and duration of visit: United States, 1975-76 

Service ordered or provided and Visits to all

Visits to dermatologists I disposition and duration of visit specialists

1 

Number in 

Service ordered or provided thousands Percent of visits 

No service ............................... ..................... ......... 

Diagnostic service (selected services): 

Limited history and/or examination .................. 

General history and/or examination .................. 

Clinical laboratory test ............. .......... ............... 

x-ray ..... ...... ...........m.c.....m...m.m.o.tr. o. ....m.mo....oc....-

Blood pressure check ......................................... 

Therapeutic service (selectad services): 

Drug prescribed ................................................. 

Injection ....................... ............ ......................... 

Immunization and/or desensitization ................ 

Office sur~~ ............ G...... .......... ....................... 

Physiotherapy ... ...................... ................ .......... 

Medical counseling ............................. ............... 

Disposition of visit (selected actions) 

No followup ............. ........................ ..................... 

Return at a specified tima ..................................... 

Return if needed ............. ...................................... 

Telephone followup .................................. ........ .... 

Referred to other physician, agency .......... ............ 

Duration of visit 

O minutesl ........... ................................................ . 

1-5 minutes ........................................................... 

6-10 minutes ......................................................... 

11-15 minutes ........ ............................................... 

16-30 minutes ............... ................................ ........ 

31 minutes or more ............... ................................ 

1,234 3.5 2.5 

17,1OB 47.9 51.6 

1,493 4.2 16.3 

1,755 4.9 22.8 

*336 0.9 7.5 

�377 1.1 33.2 

19,625 54.9 43.6 

2,085 5.9 13.1 

892 2.5 4.9 

11,126 31.2 6.9 

2,321 6.5 2.6 

4,874 13.6 13.0 

3,359 9.4 12.3 

23,812 66.7 60.2 

7,397 20.7 21.9 ~ 

838 2.4 3.5 

� 346 1.0 2.8 

1,058 3.0 1.8 

6,160 17.3 15.1 

14,481 40.5 31.5 

9fi76 27.7 26.6 

3,899 10.9 19.5 

�248 0.7 5.5 

1RePre~~ts no face.to-face contact between the patient and the physician. 

SYMBOLS 

Data not available--–---— 

Category not applicable ------------------------------ . . . 

Quantity zero -------------------------------------------- -

Quantity more.than Obut less than 0.05------ 0.0 

Figure does not meet standards of 

* reliability or precision--— 
ackweda7 

TECHNICAL NOTES 

I SOURCE OF DATA: The information	 presented

. in this report is based on data collected in the 

Nat ion al Ambulatory Medical Care survey 

(NAMCS) during 1975 and 1976. The target 

population of NAMCS encompasses office visits 

within the conterminous United States made by 

ambulatory patients to non-Federal physicians 

who are principally engaged in office practice 

and not in the specialties of anesthesiology, pathology or radiology. The National Opinion Research Center, under contract to the National 

Center for Health Statistics, was the organization 

responsible for the survey’s field operations and 

data processing. 

SAMPLE DESIGN: NAMCS utilizes a multistage 

probability design that involves samples of primary sampling units (PSU’S), physician practices 

within PSU’S, and patient visits within practices. 

Each year a sample of practicing physicians is selected from masterfiles maintained by the American Medical Association and American Osteopathic Association. The 1975 and 1976 NAMCS 

samples included 110 dermatologists, of whom 8 

wer; found not eligible for participation at the 

time of the survey. Of the 102 dermatologists 

who were eligible for participation in NA.MCS, 

81 (79.4 percent) participated in the survey. The 

sample physicians are requested to complete Patient Records5 (brief encounter forms) for a systematic random sample of office visits taking 

place within their practice during a randomly assigned weekly reporting period. The number of 

Patient Records completed by sample dermatologists was 2,665 for the 2-year period. 

Characteristics of the physician’s practice . . 

such as primary specialty and type of practice 

are obtained during an induction interview. 

SAMPLING ERRORS: Since the estimates for 

this report are based on a sample rather than the . . entire universe, they are subject to sampling variability. The standard error is primarily a measure 

of sampling variability. The relative standard 

error of an estimate is obtained by dividing the 

standard error of the estimate by the estimate 

itself and is expressed as a percent of the estifl 

5See figure 1. 

mate. Relative standard errors of selected aggregate statistics are shown in table I. The standard 

errors appropriate for estimated percentages of 

visits are shown in table II. 

Table 1. Approximate relative standard errors of estimated 

numbers of office visits,’ NAMCS, 1975-76 

Estimated number Relative standard 

of office visits error in 

in thousends percent 

6~ .. .. .. .. .... .. .. .. .. .. .. .... .. .. .. .. ... . .... . . .... .. .... .. 30.2 

lpm ... . ...... .. .. .. .. .. .. .. .. .. .... .. .. ... ... ...... .. .. ... 23.5 

2,000 . .... .... .. .. .... . ... ... .. . .. ... . .. .. .. .. . ..... . ... .... 16.7 

4.0m .. ...... .. .. .... . ... .... ...a.. .. .. .. .. .. .. .... .. .. .... . 12.0 

lo.om .. .. .. .. ..... . .. .. .. .. .. .. .... .. .. .. .. .. ...... .. .... . 8.0 

m.om .... .. .. . ... .. .. .... .. .. .... .. .. .... .. .. .... .. .. ... .. 4.8 

mo.wo . .. .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. .... .. .. .... .. 3.4 

1,000,000 .. .... .. .. .. .. .. .. .... .. .. .... .. .. .... .. . .... . .. 3.1 

Example of use of table: An aggregate estimate of 25,000,000 

visits has a relative standard error of 6.4 percent or a standard 

error of 1,600,000 visits (6.4 percent of 25,000,000). 

Table II. Approximate standard errors of percentages of estimated 

numbers of office visits, NAMCS, 1975-76 

I 

Estimated percentage Base of percentage 

(number of visits 1 or 5 or 10or 20 or 30 or 50 

in thousands) 99 95 90 80 70 

Standard error in percentage points 

600 . . ...... . ... .. .. .. .... .. 3.0 6.5 9.0 12.0 13.8 15.0 

1 ,000 .. .. .. .. .... . ... .... . 2.3 5.1 7.0 9.3 10.7 11.6 

2,000 .... .. . .. .. .. .. ...... 1.6 3.6 4.9 6.6 7.5 8.2 

4,000 .... .. .. .. . . .. ...... . 1.2 2.5 3.5 4.7 5.3 5.B 

10,000 .. .. .... .. .. .. .. .. . 0.7 1.6 2.2 2.9 3.4 3.7 

40,000 . .. . .... .. .. ...... . 0.4 0.8 1.1 1.5 1.7 1.8 

200,000 . .. .... .. .. .. .. .. 0.2 0.4 0.5 0.7 0.8 0.8 

1 ,Oocs,ooo .... .. .. .. .. .. 0.1 0.2 0.2 0.3 0.3 0.4 

Emwrrple of use of table: An eatimat e of 20 percent based on 

an aggegate estimate of 80,000,000 viaits has a standard error of 

1.3 percent. The relative standard error of 20 percent is 6.5 percent (1.3 percent+ 20 percent). 

DEFINITIONS: An ambulatory patient is an individual presenting himself or herself for personal health services who is neither bedridden 

nor currently admitted to any health care institution on the premises. 

An o~~ice is a place that the physician identifies as a location for his or her ambulatory 

practice. Responsibility over time for patient 

care and professional services rendered there 

generally resides with the individual physician 

rather than an institution. 

. 
8 admmedat’a 

A visit is a direct personal exchange between from NAMCS are physicians who are hospit s 

an ambulatory patient and a physician or a staff based; physicians who specialize in anesthesimember working under the physician’s super- ology, pathology, or radiology; physicians who 

vision for the purpose of seeking care and ren- are federally employed; physicians who treat 

dering health services. only institutionalized patients; physicians emA physician is a duly licensed doctor of ployed fuH time by an institution; and physimedicine (M.D.) or doctor of osteopathy (D. O.) cians who spend no time seeing ambulatory 

currently “in office-based practice who spends patients. -

time in caring for ambulatory patients. Excluded 

Recent Issues of A duance Data From Vital and Health Statistics 

No. 36. Contraceptive Utilization in the United States: No. 33. Office Vkits to Orthopedic Surgeons, NationaJ 

1973 and 1976 (Issued: August 18, 1978) Ambulatory Medical Care Survey: United 

States, 1975-76 (Issued: July 18, 1978) 

No. 35.	 An Overview of Nursing Home Characteristics: 

Provisional Data from the 1977 National No. 32. Sociodemographic and Health Characteristics 

Nursing Home Survey (In preparation)	 of Persons by Private Health Insurance Coverage and Type of Plan, United States, 1975 

No. 34.	 Office Vkits to Otolaryngologists, National (Issued: August 22, 1978) 

Ambulatory Medical Care Survey: United 

States, 1975-76 (h preparation) 

A complete list of Advance Data From Vital and Health Statistics is available from the Scientific and Technical 

Information Branch. 

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