The authors describe how the 8,128 medical school seniors who completed the 1993 AAMC Medical School Graduation Questionnaire (GQ) rated the influence that each of 36 factors (such as interest in helping people) had on their specialty decisions, using a 0 to 4 Likert-type scale where 4 indicated a major influence on specialty choice. The list of factors and their mean ratings are presented to show those of greatest influence (e.g., type of patient problems encountered, rated 3.44), of moderate influence (e.g., type of patients encountered; 2.75), and of limited influence (e.g., length of residency; 1.18). Factors' ratings also are compared across specialty groups. While the seven most influential factors were given about the same weight by the seniors regardless of their specialty choice, there were significant differences in the ratings of other factors across specialties (e.g., patient contact factors were rated higher by future generalists than by graduates favoring other specialties). The GQ respondents' ratings of factors over time are compared for 1991, 1992, and 1993. Last, those respondents who had changed their minds about a specialty were asked to rate the 36 factors according to how strongly they had influenced the rejection of the previous specialty choice; most of the factors were rated as having been of minor influence. As a general rule, income prospects and educational debt were not strong influences, either on specialty choice or rejection. The authors state that the influences of the factors they have reported are those that set the initial direction of graduates' residency training.(ABSTRACT TRUNCATED AT 250 WORDS)