British Joiarnal of Medictil Edircnrion. 1975, 9, 78-85

Factorial study of medical specialty preferences’ HARRISON G. G0,UGH2 Institute of Personality Assessment and Research, University of California, Berkeley, U.S.A. Key words

“SPECIALTIES, MEDICAL *CHOICE BEHAVIOUR ‘ATTITUDE OF HEALTH PERSONNEL STATISTICAL PSYCHOLOGICAL TESTS PERSONALITY ASSESSMENT CALIFORNIA

Specialization in medicine, seemingly a quintessentially modem phenomenon, in fact has ancient roots extending back into Athenian days and the Egypt of the Pharaohs (Galdston, 1958). I n these earlier epochs, specialization at times drifted away from the mainstream of medical progress, so that lithotomists, bone setters, lens couchers, fistula menders, extractionists, and even the ‘surgeons’ of the Middle Ages were often lay persons, untutored in the clinical arts and scientific bases of medical knowledge. Specialization in the last century has followed a different course, being elaborated on a firm foundation of scientific training and an appreciation of the need for a comprehensive clinical perspective of the patient’s condition as opposed to a mere technical or instrumental point of view (Galdston, 1959). In the past 40 years an increasing proportion of physicians has turned from general to specialty practice. In 1941 general practitioners and part-time specialists constituted 71 per cent of the physicians in the United States; in 1962 this proportion had dropped to 27 (White, 1964). By 1970 the percentage was down to 19, with a projected figure of only 6 per cent for 1990 (Rousselot, 1973). A follow-up of I337 physicians from the 1960 and 1964 graduating classes of American schools of medicine indiT h i s paper is based on a programme of research on medical education, choice o€ specialty, location of practice, and related issues, being carried out under a grant from the Robert Wood Johnson Foundation. *Requests for reprints to Dr Harrison G . Cough, Institute of Personality Assessment and Research. University of California. 2240 Piedmont Avenue, Berkeley, California 94710, U.S.A. 78

FACTOR ANALYSIS,

cated that almost 100 per cent had undertaken some form of residency training; the conclusion reached was that with the classification of family practice as a specialty in 1969, nearly all medical school graduates during the 1970s can be expected to take residency training and to seek specialty certification (Levit, Sabshin, and Mueiler, 1974). These trends pose important problems for medical education and manpower planning. For example: Do entry rates into the different spxialties coincide with society’s needs for a variety of medical services? Are choices of specialty determined by fortuitious as well as by rational considerations? What if any are the psychological factors that play a part in selecting one specialty rather than another? Much of the research on the issue of choice has taken single, designated specialties as target points, rather than groupings or clusters. A significant analysis in 1960 surveyed 2676 students from eight schools of medicine, seeking influences bearing on preferences for careers in basic science, internal medicine, pathology, paediatrics, surgery, obstetrics-gynaecology, public health, and psychiatry (Coker, Back, Donnelly. Miller, and Strickland, 1960). Bruhn and Parsons (1964, 1965) sent out questionnaires to 199 preclinical and 144 clinical students at the W.niversity of Oklahoma medical school to ascertain their attitudes toward surgery, internal medicine, psychiatry, and general practice, Schumacher’s (1 964) analysis w3,s based on interns from graduating classes of that year who expressed interest in full-time medical or surgical practice, part-time medical or surgical practice in conjunction with

Specialty preferences

research and teaching and in full-time general practice. Boverman (1965) reported the career preferences of 723 graduating seniors from a decade of classes at the University of Chicago school of medicine, classifying responses under medicine, surgery, psychiatry, paediatrics, general practice, basic science, pathology, and no choice or undecided. Kritzer and Zimet (1967) dealt with 120 residents a t the University of Colorado in medicine, obstetrics-gynaecology, paediatrics, psychiatry, and surgery. Mawardi’s (1965) survey a t Case-Western Reserve aimed to include 160 graduates in the specialties of medicine, surgery, psychiatry, paediatrics, and obstetrics-gynaecology, and also physicians in full-time hospital or full-time medical school appointments. Other representative studies of attitudes, preference, or choice using designated single specialties are those of Fishrnan and Zimet (I972), Geertsrna and Grinols (1972), Paiva and Haley (1971), and Zimny and Thale (1970). There is also a similar tradition of inquiry in Britain in which attention is centered on students and doctors choosing different career pathways (Last and Stanley, 1968). These studies tend to agree concerning preferences for or choice of the various specialties. For the 10% random sample of American medical school graduates of 1960 and 1964 surveyed by Levit et al. (1974), self-identified specialty areas, in decreasing frequency, were as follows: internal medicine, 18%; surgery (all branches), 16% ; family medicine, including general practice, 13YO; psychiatry and neurology, 10%; paediatrics, 8 % : obstetrics and gynaecology, 6%; radiology, 6 % ; anaesthesiology. 4 % ; ophthalmology, 4% ; pathology, 4%; otolaryngology, 3%; urology. 3%; dermatology. 1%; preventive medicine, 1%; all others, 2%. For the 1475 British physicians reporting to Last and Stanley (1968), the figures were these: general practice, 28%; surgery, 14%; internal medicine, 11%; anaesthesiology, 7% ; obstetrics and gynaecology, 7 % ; paediatrics, 7% ; dermatology, ENT. and ophthalmology, 5 % ; psychiatry, 4%; pathology, 4%; public health, 3%; radiology, 2 % ; basic sciences, 2 % ; all others, 7 % . A second and much smaller group of studies has dealt with self-report inventory measures

19

in an effort to identify factors predictive of interest in a specialty and eventual choice of that specialty. The first such attempt was that by Strong and Tucker in 1952. They administered their materials to a sample of some 1500 established medical specialists in internal medicine, surgery, pathology, and psychiatry, and then developed scales from items differentiating the responses of one subgroup from those of the others. A fo!Iow-up was completed in 1960, of 783 medical school seniors who had been scored on these scales in 1950 (Tucker and Strong, 1962). Unfortunately, none of the scales succeeded in forecasting future choice of specialty. An obvious difficulty in these analyses is that the scoring of the inventory was based upon the responses of established physicians, whereas the forecasts of interest were those derived from the test protocols of students. A more appropriate methodology would be to construct the original scales from inventory blanks obtained from students whose later specialty choices could be determined. This method has recently been appIied by Athelstan and Paul (1971), who derived scales for general surgery, obstetrics and gynaecology, paediatrics, and psychiatry from the protocols of 1583 students. Scales were attempted for general practice and internal medicine, but these analyses did not produce enough differentiating items to warrant further attention. Initial evaluation of the Athelstan-Paul scales suggested a high false-positive rate; i.e. students scoring high on any one of the scales tended not to end up in that specialty. Another current programme of research of this kind is that being conducted by Zimny and his associates at St. Louis University (Zirnny and Senturia, 197321, b). Zimny’s Medical Specialty Preference Inventory contains items directly relevant to medical practice, and is intended for use in the counselling of medical students as well as in predictive studies of their eventual careers. A third set of inquiries has gone beyond the designation of single specialties, in an effort to identify clusters of groupings. With as many as 80 or more named specialties or kinds of practice, some sort of conceptual mapping seems to be imperative. The unattractive alternative is the dissipation of one’s energies in an

80

Harrison

exceedingly fractionated quest for psychological and other variables related to each and every category. One study that sought broader, more functional grouping of specialties was that of Wasserman. Yufit, and Pollock (1969). They classified choices as surgical and technical, person oriented, mixed, or other. Surgical-technical included surgery, orthopaedics, neurosurgery, urology, ophthalmology, pathology, anaesthesiology, and radiology. Person oriented included internal medicine, paediatrics, and psychiatry. Mixed included general practice, obstetrics-gynaecology, dermatology, otolaryngology, and neurology. Other included public health and undecided. The distribution of choices of 58 University of Illinois graduates seven years after taking the MD were: 50% surgical-technical, 25% person oriented, and 25% mixed; no graduate was in the fourth category. Renshaw and Pennell (1971), in their analysis of the distribution of women physicians in 1969, also used a classificatory system, consisting of: general practice; medical specialties (allergy, cardiovascular, dermatology, gastroenterology, internal medicine, paediatrics, and pulmonary); surgical specialties (general surgery, obstetrics-gynaecology, ophthalmology, orthopaedic surgery, otolaryngology, plastic surgery, other surgery); and other specialties (anaesthesiology, neurology, occupational medicine, pathology, psychiatry, physical medicine, preventive medicine, public health, radiology, and other specialties). Women, who constituted 6.7% of all active physicians in the country as of the date of the analysis, constituted 4.2% of those in general practice, 9.0% of those in medical specialties, 2.4% of those in surgical specialties, and 8.1% of those in the other specialties. The most directly relevant study to the new work to be reported below is that of Otis and Weiss (1973). They examined the stated preferences of 152 medical students at the University of New Mexico, in regard to 15 specialties and six settings for practice. A 21 X 21 correlation matrix was computed, and reduced by means of a Tryon-Bailey cluster analysis. Five clusters were identified: referral specialties, including ophthalmology, otorhinolaryngology,

G. Goicgh

dermatology, and anaesthesiology; academicresearch, including research, basic medical education, and education; institutional practice, including public institutions and private institutions; and primary care, including family medicine and general practice, obstetricsgynaecology, epidemiology, and paediatrics. Four of the medical specialties they copsidered did not gain significant loadings on any cluster : internal medicine, psychiatry, radiology, and pathology. The clarity of the conceptual mapping of the domain of medical specialization in this study is somewhat impaired by the inclusion of practice settings, and by the limitation of the specialties themselves to only 15. A longer listing of specialties would produce a more definitive picture, and would also permit the inclusion of closely related variants. A rule of thumb in factorial work is to represent each important component by at least two measures: this safeguard helps to make sure that significant components are not misidentified as residuals. Method and procedure A questionnaire listing 40 medical specialties (including general practice) was drawn up and sent to a random sample of 187 graduates from the classes of 1964 to 1971 of the University of California, San Francisco, School of Medicine. These 40 specialties included major categories such as internal and family medicine, surgery, and paediatrics, and also smaller specialties such as allergy and geriatrics. In every instance, an attempt was made to include at least one variant (e.g. psychiatry and child psychiatry) to avoid the problem of underdethed dimensions. Because of the length of the listing and time required to furnish the ratings, not all medical specialties could be included; nuclear medicine, emergency medicine, infectious diseases, surgery of the hand, and pulmonary illnesses are among the specialties that were not included. Completed forms were returned by 136 male and 20 female respondents. A preference rating was given to each item, ranging from + 3 (a very attractive specialty to the respondent) to 0 (neutral or uncertain) down to -3 (a very unattractive specialty). For purposes of scoring and analysis, these ratings were converted to the

Special0 preferences

positive scale 7-6-5-4-3-2-1. Table 1 gives mean preference ratings and standard deviations for the male and female samples, and also lists the 40 specialties used in this study. There are nine items on which the male physicians assigned significantly higher ratings than did the females: abdominal, cardiovascular, colon and rectal, general, head and neck, orthopaedic, thoracic, and traumatic surgery, and urology. The surgical theme running through all nine specialties is self evident. The women physicians assigned significantly higher ratings to dermatology, paediatrics, preventive medicine, and public health. Though there are significant differences in the ratings of male

81

and female physicians, the similarities should not be overlooked. The five highest-rated fields for the male doctors were internal medicine, family medicine, general practice, cardiovascular diseases, and paediatrics; four of these were also in the set of five highest-rated fields for the female doctors; paediatrics, general practice, family medicine, internal medicine, and obstetrics-gynaecology. Another indication of similarity is the correlation of 0.44 between the two columns of mean ratings. The next step in the analysis was the computation of the 4 0 x 4 0 matrix of interconelations among the preference ratings. This was done for males and females separately, and

Table 1. M e a n specialty preference ratings f o r male a n d female physicians Men (136) . ,

Specialiies Allergy Anaesthesiology Cardiovascular diseases Dermatology Endocrinology Family medicine Gastroenterology General practice Geriatrics Gynaecology Haematology Immunology Internal medicine Neurology Obstetrics Obstetrics and gynaecology Ophthalmology Otology 0tolaryngology Pathology Paediatria Physical medicine Preventive medicine Psychiatry Child psychiatry Public health Radiology Diagnostic radiology Rhinology Abdominal surgery Cardiovascular surgery Colon and rectal surgery General surgery Head and neck surgery Neurological surgery Orthopaedic surgery Plastic surgery Thoracic surgery Traumatic surgery Urology 'Mean higher, PL0.05. *"Mean higher, P&O.Ol.

M 3.04 3.63 4.48 3.4 1 4.2 I 5.06 4.21 4.74 2.76 3.70 3.79 3.77 5.1 1 3.71 3.68 3.80 4.18 3.40 3.55 3.12 4.24 2.72 3.33 3.24 3.04 3.26 4.02 4.04 2.79 4.04 4.01 3.46 4.19' 3.57' 3.0 1 4.07 * 3.74 3.94' 4.19' 3.62' '

SD 1.70 1.83 1.70 1.82 1.60 1.73 1.57 1.91 1.82 1.86 1.61 1.71 1.60 1.53 1.93 1.89 1.52 1.49 1.56 1.82 1.90 I .47 1.90 2.1 1 2.02 1.92 1.62 1.65 1.34 1.90 1.97 1.82 1.95 1.80 1.78 1.94 1.97 1.91 1.97 1.82

3.55 3.80 3.80 4.45 4.05 4.70 3.60 4.75 2.65 4.50 405 425 4.70 3.65 4.40 4.60 4-35 3.25 3.05 3.40 5.15' 3.10 4.25' 3.65 3.80 4.40* 4.00 3.95 2.50 2.80 2-60 2.40 290 2.30 2.25 2.35 2.90 2.40 2.70 2.15

1.79 1.82 -I .77 .. 1.82 1.85 2.1 1 1.64 1.68 1.60 1.32 1.76 2.02 1.72 1.79

1.73

1.60 1.50 1.71

1.64 ..

1.93 1.90 1.48 1.74 2.08 2.24 1.54 1.69 1.54 1.05

1.88

1.85 1.76 2.02 1.56 1.65 1.84 1.86 . ..

1.73 2.05 1.22

Harrison G. Goirgh

82

surgical specialities were included in the original list on the possibility that they would diverge from the more general factor (e.g. orthopaedic and plastic surgery). This, however, did not occur and the findings indicate that there is a strong basic factor of surgical interest that expresses itself in all aspects and kinds of surgical practice. In the light of this finding, the decision to use ‘surgery’ as a target category in previous studies of specialization appears to be valid. Factor 2 is defined by highest loadings on internal medicine, cardiovascular diseases, endocrinology, gastroenterology, and haematology, and is easily recognized as an internal medicine specialty. This factor is also in agreement with the ad hoc decisions of earlier studies to use internal medicine as a target category. Factor 3 includes otology, otolaryngology, rhinology, and ophthalmology. It is worth noting that ophthalmology, as a preference, does not split off from the other three to define an independent factor. Physicians in practice may limit their activity to the eye, but their pattern of interests, this factor suggests, will extend broadly enough to include ear, nose, and throat as well. Factor 4 is composed of psychiatry and child psychiatry, with subordinate loadings on public health and preventive medicine. Neurology - often linked to psychiatry in teaching departments - is significantly correlated with this psychiatry factor, but has a stronger affiliation with the internal medicine dimension. Factor 5 is defined by obstetrics and gynaecology. Factor 6 is composed of radiology and diagnostic radiology. Factor 7 is principally defined by general practice and family medicine, with a lesser contribution from paediatrics. Factor 8 has its highest loading on Interpretation of factors physical medicine, followed by geriatrics and Factor 1 is clearly a surgical factor, with dermatology. The 9th and final factor is deloadings of 0.70 or above on all 10 of the desig- fined by allergy, immunology, paediatrics, and nated surgical specialties, and in addition a haematology . loading of 0.73 on urology. Several of the Table 2 may also be scrutinized for named specialties that do not, in fact, define a func‘The complete 40 X 40 correlation matrix i s available tionally independent dimension of variation. on request from the Institute of Personality Assess- One of these is pathology. Interest in patholment and Research, University ol California, Berkeley, ogy, it appears, is subordinate to interests in California. 94720 U S A .

also for the total sample of 156 Ss. Because of the moderately high correlation between the male and female matrices (r=0.61), a decision to carry out the factor analysis on the matrix for the total sample was deemed acceptable. The small size of the female sample (N=20) would give rise to unreliable factorial findings if analysed by itself. The full matrix of 780 correlations is too large to be reported in this paper, but representative values can be mentioned’. For example, internal medicine correlated 0.60 with cardiovascular diseases, 057 with haematology, 0.50 with gastroenterology, 0.21 with otoIaryngology, and -0.26 with orthopaedic surgery; family medicine correlated 0.82 with general practice, 0.44 with paediatrics, -0.10 with urology, and -0.22 with radiology; obstetricsgynaecology correlated 0.41 with general practice, 0.31 with abdominal surgery, and -0.24 with immunology; pathology correlated 0.42 with rhinology. 0.41 with otology, and -0.17 with family medicine. A principal component factor analysis was carried out on the 40 X 40 matrix, using squared multiple correlations in the diagonals and terminating the extraction of factors when eigen values fell below 1.00. The purpose of this analysis was to identify a subset of underlying psychometric dimensions from which the observed covariation of ratings among the 40 specialties could be recomputed. Nine factors were generated by this analysis. These factors were then rotated by means of Kaiser’s varimax technique, so as to apportion maximal variance to each factor. Table 2 presents the loadings of each of the 40 specialties on the nine factors defined in this way. The proportion of total communality accounted for by each factor was 0-218, 0.095, 0-093, 0.077, 0.075. 0.055, 0.050, 0-045, and 0.038.

-

Allergy Anaesthesiology Cardiovascular diseases Derma tology Endocrinology Family medicine Gastroenterology General practice Geriatrics Gynaecology Haematology Immunology Internal medicine Neurology 0bs tetrics Obstetrics and gynaecology Ophthalmology Otology Otolaryngology Pathology Paediatrics Physical medicine Preventive medicine Psychiatry Child psychiatry Public health Radiology Diagnostic Radiology Rhinology Abdominal surgery Cardiovascular surgery Colon and rectal surgery General surgery Head and neck surgery Neurological surgery Orthopaedic surgery Plastic surgery Thoracic surgery Traumatic surgery Urology

Specialties -

~~

0.8 1 0.52

-0.16 -0.17 0.09 0.16

0.02

0.09 0.05 0.30 0.28 0.29 0.26 0.11 0.05 0.18

0.09 0.02 -0.05

-0.04

0.89 0.87 090

0.84 0.71 0.76 0.70 092 0.90 0.73 0.02 -0.18 -0.09 0.0 1 -0.10 -0.05

-0.03 0.00 0.24 0.20 0.74 0.05

-0.05

0.1 1 0.72 0.89 0.88 0.42 0.04 0.1 1 -0.0 1

0.05

-0.01 -0.01 0.1 1 0.12 0.03

0.12

0.06 -0.10 -0.06 0.02

-0.10

-0.08

-0.11 0.09

-0.07 0.29 0.04

0.01

0.18 0.23 0.20 0.26 0.18 -0.12 0.09 -0.27 -0.18 -0.17 -0.38 0.24 0.26 0.22 0.89

-0.04

0.53

0.05 0.12 0.14 0.08 0.20 -0.13

-0.10

-0.15

-0.14 0.16 -010 -0.05 -0.10 -0.07 -0.14

0.05 0.09

0.04

-0.02 0.02 0.00 0.16

0.07 0.14

0.1I

-0.09 -0.13 -0.09

0.16 -0.03 0.27 0.06 0.04 0.25 -0.11 -0.08 0.04 0.17

0.10

0.92 014 0.02 0.01

-0.1 1 0.90

-0.10

0.06 0.47 0.24 058 0.80 0.88 0.59 0.02 -0.02 0.06 -0.1 1

-0.07

0.01 0.01

0.08

0.04 0.22 0.45 0.10

0.00

0.03 027 0.01 029 0.06 087 -0.12

0.1 1

003

-0.05 0.0 I 0.29 -0.03 0.23 016 0.07

-0.08

0.26 0.05 -0.09 -0.10 0.03 0.02 0.11 -0.07

0.00

0.76 0.38 0.74 0.20 0.71 0.09 0.32 0.00 067

003 -0.34

0.47

Factor londitigs 5 0.16 0.1 1

0.1I

0.15 -0.07

-0.25 0.1 1

4

0.21 -0.22

3

2

I

Table 2. Loadinns of each specialty after varimax rotation o f 9 preference factors 6

0.12 -0.14 -005 0.06 0.13 0.10 0.01

0-10 0.09

018

0.00 0.06 008 0.05 0.38 -0.02 0.09 0.24 -0.08 -0.07 0.24 0.84 0.84 0.25 0.12

0.22 -0.03 0.00 -0.19 0.00 -0.20 -0.09 -0.12 0.07 0.10 0.0 I -0.1 1 0.00

0.07 0.38

7

0.04 -0.17 007 0.00 0.04 0.04 -0.23

0.03 015

000

0.14 -0.02 -002 000 -0.18 048 007 0.06 0.15 0.14 0.10 -0.15 -0.13 001 011

0.19 001 -0.19 0.73 0 06 0.75 036 012 0 04 -0.13 0.16 -0.03 014

0.02 0.3 5

8

0.08 0.07 -0.08 -0.04 0.22

0.00

-0.04

0.03 0.04

-013

-0.04

0.77 0.42 0.12 0.01 0.26 0.00 0.03 0.12

-0.08

0,17

0.03 -0.15 0.09 0-10

-0.01 0.44 0.06 0.20 0.08 0.18 0.62 0.08 -0.06 0.03 0.03 0.07 -0.04

0.26 -0.07

9

-0.01 -0.08 -0.03 -0.07 -0.10

-0.03 -0.08

-0.02 -0.08

0.00

0.49 0.23 -0.14 0.07 0.19 -0.08 0.06 0.05 0.12 -0.06

0.06 -0.05

-0.01 -0.09 0.02

0.29 0.15 -0.01 - 0.02 -0.04 -0.13 -0.02 0.44 0-58 -0.06 0.09 009

- 0.08

0.63 0.10

2 2

I .

2

u'

k

t,

B3.

84

Harrison G . Gougti

other more dominant themes of preference such studies would also be of interest, comparing as eyes, ears, nose, and throat, radiology, and to the profiles of physicians expressing satisfaction a much lesser extent surgery. A psychological or dissatisfaction with their present areas of inventory scale to forecast interest in pathology, practice. A third kind of inquiry could evaluate it follows, would be more difficult to construct the degree to which medical students and and validate than one for a more central dimen- physicians would find something of value in the sion of specialty preference. This comment may examination of their own profile of scores on be referred back to the failure of the Strong- the self-report instrument. Implicit in these Tucker interest scale for pathology to hold up comments is the belief that factorial study represents only a first step in a programme of in their 10-year longitudinal study. research. The significance, if any, of the dimenAnother specialty frequently used as a target sions detected by this methodology must be variable in earlier work is paediatrics. The determined by evidence to be gathered in analyses in Table 2 suggest that this is aIso a follow-up investigations. ‘weak’ specialty in the sense that it lacks a distinguishing pattern of interests and preferences. A physician in paediatric practice may well be one equally suited, from the standpoint References of personal preferences, to practice in eyes, ears, Athelstan, G. T., and Paul, G. J. (1971). New nose, and throat, family medicine, or allergyapproach to the prediction of medical specialization : student-based Strong Vocational Interest immunology.

Blank scales. Journal of Applied Psychology, 55. 80-86.

Concluding comments The goal of this study was to seek a reconceptualization of medical specialty preferences, in such a way as to reduce the component dimensions from the 80 or more known kinds of medical practice down to a clearer and more analytical set of underlying factors. The analyses reported above suggest that such a reduction is possible, and that something of the order of nine major facets of preference among specialties are discernible. Studies of interests, personality, and other variables predictive of the career pathways of physicians should pay attention to underlying dimensions such as these, in addition to and perhaps in place of the common concern with designated practices offering specialty certification. In the psychological realm, one could propose a self-report inventory scored for these nine factors. The profile that would be generated by plotting the nine scores of an individual on a standard grid could then be used in counselling, and in future research on the validity of the conceptual system. Prospective studies of this kind would be of considerable interest, e.g. test scores could be obtained while Ss were in premedical or medical training and then validated against career choices manifested in later professional life. Concurrent

Boverman, H. (1965). Senior student career choices in retrospect. Joicrnal of Medical Edircaiion. 40, 161165.

Bruhn. J. G., and Parsons, 0. A. (1964). Medical student attitudes toward four medical specialties. Journal of Medical Education, 39, 40-49. Bruhn, J. G.,.and Parsons, 0. A. (1965). Attitudes toward medical specialties : two follow-up studies. Journal of M e d i c d Education, 40, 273-280. Coker, R. E., Jr., Back, K. W., Donnelly, T. G., Miller, N., and Strickland, L. H. (1960). Patterns of influence: medical school faculty members and the values and specialty interests of medical students. Journal of Medical Education, 35, 518527. Fishman, D. B., and Zimet, C. N. (1972). Specialty choice and beliefs about specialties among freshman medical students. Journal of Medical Education. 47, 524-533. Galdsion, I. (1958). The birth and death of specialties. Journal of the American Medical Association, 167, 2056-2061. Galdston, I. (1959). The natural history of specialism in medicine. Journal of rhe R rnerican Medical Associaiion. 170, 294-297. Geertsma, R. H., and Grinols, D. R. (1972). Specialty choice in medicine. Journal of Medical Education, 47, 509-517. Kritzer, H., acd Zimet, C . N. (1967). A retrospective view of medical specialty choice. Journal of Medical Education, 42, 47-53.

Last, J. M., and Stanley, G. R. (1968). Career preference of young British doctors. British Journal of Medicul Education. 2, 137-155.

Specialty preferences

Levit, E. J., Sabshin, M., and Mueller, C. B. (1974). Trends in graduate medical educahon and specialty certification. N e w England Journal o f Medicine, 290, 545-549. ,

Mawardi, B. H. (1965). A career study of physicians. Journal of Medical Education, 40, 658-666. Otis, G. D., and Weiss, J. R. (1973). Patterns of medical career preference. Journal o f Medical Education, 48, 1116-1123. Paiva, R. E. A., and Haley, H. B. (1971). Intellectual, personality, and environmental factors in career specialty preferences. Journal of Medicul Education, 46, 281-259. Renshaw, J. E., and Pennell, M. Y.(1971). Distribution of women physicians, 1969. Woman Physician, 26, 187-195. Rousselot, L. M. (1973). Federal efforts to influence physician education, specialization distribution projections and options. American Journal of Medicine, 55, 123-130. Schumacher, C. F. (1964). Personal characteristics of students choosing different types of medical careers. lorirnal o f Medical Edrccnrion, 39, 278-288.

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Strong, E. K., Jr., and Tucker, A. G. (1952). The use of vocational interest scales in planning a medical career. Psychological Monographs, 66 (9, Whole NO. 341), 1-61. Tucker, A. C., and Strong, E. K., Jr. (1962). Ten-year follow-up of vocational interest scores of 1950 medical college seniors. Journal o f Applied Psychology, 46, 81-86. Wasserman, E., Yufit, R. I., and Pollock, G. H. (1969). Medical specialty choice and personality. 11. Outcome and postgraduate follow-up results. Archives of General Psychiatry, 21, 529-535. White, K. L. (1964). General practice in the United States. lournal of Medical Education, 39, 333-345. Zimny, G., and Thale, T. (1970). Specialty choice and attitudes toward medical specialties. Social Science and Medicine, 4, 251-264. Zirnny, G. H., and Senturia, A. G. (1973a). Medical specialty counseling: a survey. locirnal of Medical Education, 48, 336-342. Zimny, G. H., and Senturia, A. G. (197313). Medical student utilization of the Medical Specialty Preference Inventory. Journal o f Medical Education, 48, 1019-1020.