Table 2. Studies included in critical review.

Source	Research question	Method	Measures	Population	Sample size	Response rate	Methodological limitations
Barondess and Glaser 199326	What are the attitudes that lead potential medical school applicants towards or away from medical school?	Survey / Cross-sectional	Attitudes towards medical careers--such importance of job satisfaction, stability of career, and ability to help those who are less fortunate in choosing a medical career	National sample of college students and premedical advisors from 100 US schools	Study 1: total sample 1780 students (1003 non-applicants to medical school; 500 medical school applicants; 227 qualified non-applicants); Study 2:93 premedical advisors	Study 1: Student groups: 84-89%; Study 2: Premedical advisors: 93%	Limited information provided regarding interview items or whether items were pretested.
Barr et al 200827	What are the causes, among underrepresented minority students, of a decline in interest in pursuing a career in medicine?	Study 1: Survey/ Longitudinal; Study 2: Follow-up interviews with subset of Study 1 survey participants	Survey measure: 10-point scale of interest in premedical studies. Interviews asked about factors leading to a change in interest, the role of coursework in changing interests, and important skills or resources premedical students need to succeed	Incoming freshman college students who indicated interest in medicine and completed all 3 surveys, Stanford University	Study 1: 362 students; Study 2:68 students	Study 1: Initial response rate to survey invitation not reported; 34.3% of 1056 T1 respondents completed all 3 surveys; Study 2: Not reported	Limited generali-zability - sampled only from one university, which is among the most selective nationally; Students self-selected to take the survey; High rate of attrition over time
Barr et al 201028	Do negative experiences in chemistry courses contribute to undergraduate students discontinuing premedical studies?	Study 1: Sur-vey/Repeated Measures; Study 2: Follow-up interviews with subset of survey participants	Survey measure: 10-point scale of interest in premedical studies. Interviews asked about factors leading to a change in interest, and to identify courses that discouraged interest	Incoming freshman college students who indicated an interest in medicine, UC Berkeley	Study 1: 1036 students; Study 2:63 students completed follow-up interviews	Study 1: Initial response rate to survey invitation not reported; 57% of the 1036 T1 respondents also responded at the end of their second year; Study 2: Not reported	Limited generali-zability- sampled only from one university, which is among the most selective nationally; Students self-selected to take the survey; Initial response rate not reported; High rate of attrition over time; Students not individually identified so unable to track individual change over time
Chuck 199632	What are premedical students’ expectations from a medical career?	Survey/ Cross-sectional	Expectations of a medical career such as the ability of physicians to cure and help their patients, to have intellectually satisfying work, or to have to perform administrative duties	Study 1: premedical students, UC Berkeley and Cal State Hayward; Study 2; practicing physicians from similar geographic area	Study 1:84 premedical students; Study 2:251 practicing physicians	Study 1: premedical students: 100%; Study 2: physicians: 62%	Possible limited generalizability because this sample of premedical students may be more engaged than the general population of premedical students; No statistical tests of magnitude of between-subjects comparisons
Colquitt and Killian 199125	Why do students who take the MCAT opt to not apply to medical school in the years 1986 and 1988?	Study 1: Secondary data analysis; Studies 2 & 3: Survey/ cross-sectional with open ended response	Reasons for not applying to medical school, attitudes about medical practice	Study 1: MCAT examinees; Studies 2 & 3: non-applicants to medical school (took MCAT but did not apply)	Study 1: secondary data analysis (n/a); Study 2: 539 non-applicants (1986); Study 3: 745 non-applicants (1988)	Study 1: secondary data analysis (n/a); Study 2: 35% (1986); Study 3: 32% (1988)	Self-selection bias possible due to low response rate (authors used weighted analysis to correct for non-response bias)
Conrad 198640	How prevalent is the premedical cut-throat stereotype in reality? Despite a low prevalence, why does the myth still exist?	Interviews/ Cross-sectional	Asked interviewees about the premedical sub-culture, and conducted fieldwork in premedical settings	Premedical students, Brandeis University	30 premedical students	Potential participants approached– not reported	Half of sample was convenience sample; Limited generalizability to other institutions due to selective, private nature, small institutional size, and high focus on premedical program at Brandeis
Fiorentine 198723	What causes the premedical persistence gap? Why do more men persist in premedical studies than women?	Study 1: Secondary data analysis; Study 2: Interviews/ Cross-sectional	Student academic achievement, persistence (continuing with premedical studies, application to medical school), interviews focus on why students want to become doctors	Study 1: academic transcripts of likely premedical students; Study 2: interviews with premedical students (GPA 2.50-3.50), SUNY Stony Brook	Study 1: total sample 673 students (323 females, 350 males); Study 2: total sample 27 students (16 females, 11 males)	Study 1: n/a; Study 2: Potential participants approached – not reported	“Premedical” as defined by author could include students who were not actually premedical; limited detail given of development of interview protocol or selection of interview participants; Study 2: Limited generalizability due to small sample size for interviews; Inferences and conclusions made from interview responses reach beyond scope of data
Fiorentine and Cole 199224	Why do fewer women apply to medical school if they are as likely as men to get into and through medical school?	Study 1: Interviews/ Cross-sectional; Study 2: Interviews with subset from Study 1; Study 3: Interviews/ Cross-sectional with separate population	Student academic achievement (transcripts) and application to medical school status, self-reported measures of persistence, level of encouragement perceived, and family formation plans	Study 1: 542 persisting and defecting premedical students currently enrolled at time of study, SUNY Stony Brook; Study 2: 36 premedical students; Study 3: 62 high school students with premedical plans	Study 1: total sample 542 students (240 females, 302 males); Study 2: total sample 36 students (23 female, 13 male); Study 3: 62 students	Study 1: 542 of 543 (99.8%) students participated in telephone interview; Study 2: Potential participants approached – not reported; Study 3: 62 of 62 (100%) eligible interviews completed	Limited detail given of development of interview protocol or selection of interview participants; Selective attrition due to defection from premedical program; Lack of transparency in reporting results (study samples grouped)
Hackman et al 197933	What are the perceptions of premedical students held by both premedical and non-premedical students?	Survey/ Cross-sectional with closed and open-ended responses	Ratings of students' feelings towards other student groups (i.e. Premed, pre-law, etc)	Undergraduate college students, Yale	Total sample 317 students (132 sophomores and 106 seniors randomly selected, 79 seniors who applied to medical school)	65.40%	Limited generalizability - sampled from one private selective university.
Horowitz 201039	What achievement goal orientations are adopted by premedical students? How does this differ by subject, major, requirements?	Semi-structured interviews	Main interview question: "In which subject areas do you choose courses just to get an easy A and in which subject areas do you choose more challenging courses because of an interest or a desire to learn?"	Undergraduate college students who completed Organic chemistry during 2006-07 year at a small, all-male, liberal arts college contained within a private Jewish university in the northeastern U.S.	Total sample 30 students (87% premedical; 84% majoring in biology or chemistry.	31 (54.4%) of the 57 students completing organic chemistry agreed to participate – data from 30 interviews reported	Limited generalizability – low response rate, sampled from one small, all-male, private, northeastern US, Jewish university
Klink et al 200831	Is there a relationship between premedical and non-premedical students’ perceived level of family support and confidence in their abilities to cope with premedical life?	Survey/ Cross-sectional	Scale of coping efficacy, self-reported measures of family support	Premedical, University of Wisconsin.	Total sample 238 students	57% of expected estimate of participants responded	Limited generalizability – low response rate, sampled from one large, competitive, Midwestern university; Study used limited dimensions of family support which may be related to coping efficacy.
Lewis 198538	Does the career choice of medicine influence a premedical student to undertake certain types of coursework at a liberal arts college?	Study 1: Survey/ Cross-sectional; Study 2: Sur-vey/Longitudinal of subset from Study 1.	Self-reported measures of career goals, degree goals, college major, personality traits, and interactional styles	Study 1: Premedical and non-premedical students in three classes 1982, 1983, 1985, Macalester College, St. Olaf College; Study 2: Classes 1983 and 1985 resurveyed.	Study 1: Total sample 345 students (58 premedical, 99 biology/chem majors, 187 others); Study 2: Not reported.	Study 1 & Study 2: Potential participants approached – not reported	Study 1 & 2: Limited generalizability- sampled from two small, liberal arts colleges; Data presents limited means of testing study hypotheses; Study 2: No population data or report on loss to follow-up.
Lovecchio and Dundee 200229	How do premedical and former premedical students differ on perceptions of a medical career and reasons for desiring a medical career? How does this differ by years in school and by gender?	Survey/Cross-sectional using two different questionnaires.	Self-reported career aspirations and reasons for leaving the premedical track	Current premedical students and former premedical students, McDaniel College	Total sample 97 students (44 former premedical, 53 current premedical)	100%	Limited generalizability because convenience sampling method, small sample size, and sampled from one, small, private liberal arts college; Upper-classmen disproportionately represented in both comparison groups.
Manaster et al 197635	How do incoming premedical students’ attitudes about medicine compare to those who are currently applying to medical school? How does this differ by gender?	Survey/Cross-sectional	Self-reported measures of social background, perceptions of medicine and medical school, perception of family relations, parents, and self during childhood, personality items that assess anxiety, extraversion, and internality	Incoming premedical students and premedical students applying to medical school, University of Texas	Total sample 554 students (372 incoming premeds, 182 premeds applying to medical school)	Potential participants approached – not reported	Limited generalizability- sampled from one, large university; Skewed male/female ratio; Limited detail if/how questionnaire was pretested; How measured variables related to impact of collegiate experience on occupational goals not clearly defined.
McCranie and Lewis 198736	What is the prevalence of Type A behavior among premedical students and students pursuing other courses of study?	Survey/ Semi-longitudinal	Self-reported measure of Type A behavior, and measures of involvement with premedical studies	Premedical students and non-premedical students from 13 private, liberal arts colleges in the Associated Colleges of the Midwest.	Total sample 253 students (118 premed, 73 bio/chem majors, 62 other majors)	47.9% of initial sample responded to questionnaire; Groupings made to resurvey a subset of 336 where 75.3% responded.	Limited generalizability – low response rate, sampled disproportionally from predetermined groups and sampled from small private liberal arts college; Selective attrition
Pascarella et al 198730	What are the direct and indirect effects of undergraduate college experience on occupational attainment in medicine?	Survey/ Longitudinal- Qualitative causal modeling	Self-reported measures of family background, secondary school experiences, initial occupational aspirations, and personal characteristics	National sample of premedical students, enrolled in a 4 year undergraduate institution in 1971, who responded to national CIRP survey; followed over 9 years.	Total sample 454 premedical students	Secondary data analysis (n/a)	Selective attrition- difficult to assess effects of aspiration changes with single follow-up; Secondary analysis of existing data- survey not designed around research question and weak operational definitions model variables. (i.e., the 4 college experience variables limited in how they assess the “experience” of the student.)
Sade et al 198434	Does the anecdotally documented “premedical syndrome” exist in reality and what traits comprise is?	Study 1: Survey/Cross-sectional; Study 2: Survey/Cross-sectional	Self-reported ratings of premedical students on 14 different traits, and self-reported major of study	Study 1: Premedical and non-premedical students from 13 colleges in South Carolina; Study 2: Faculty members 13 colleges in South Carolina	Study 1: total sample 498 students; (253 premed, 245 randomly sampled non-premed); Study 2: 403 faculty	Study 1 & 2: Potential participants approached – not reported	Limited generalizability- sampled, small, colleges in one southern state; Data are limited to perceptions and not direct observations; Limited information on items in questionnaire and if it was pretested.
Simmons 200537	What are the attitudes of premedical students towards breadth of education?	Study 1: Interviews; Study 2: Focus group interviews with subset of Study 1 participants	Interviews and focus groups focused on student attitudes towards educational breadth	Study 1: Premedical students, junior and senior years, Centerville University	Study 1:15 students; Study 2: 7 students	Study 1:23 of 1100 (.02%) students responded to initial solicitation; 16 (69%) completed interview and 1 eliminated based on study criteria; Study 2: Not reported.	Limited generalizability- sampled one university, focused on liberal arts education; Self-selection bias due to small sample size drawn from large web recruitment effort; Selection bias due to purposeful sampling technique; Selection bias towards students who remain in the premed program because sample of upper classmen; Skewed male/female ratio.
Staley and Hood 197722	What are the causes of higher attrition rates for women in premedical pro-grams?	Longitudinal survey	Self-reported measures of student family characteristics, personal and educational background, and past and future medical career plans	Premedical students, in their freshman and sophomore years, University of Iowa	Total sample 188 students (99 female, 89 male)	Initial response rate to survey invitation not reported; Sample population at T1:89% of females (106); 81% of males (98); Sample population at T2: 93% females (99); 91% males (89)	Limited generalizability- sampled one, large Midwestern university; Selective attrition; Sampling times exclude measurement of changes to perceptions over time after sophomore year; Limited information on items in questionnaire and if it was pretested.