Salary schedules for 1962-63 to 1967-68 were obtained from school districts in 11 standard metropolitan statistical areas to test two hypotheses: (1) The amount of postgraduate education of elementary and secondary teachers is directly related to the salary policy of the employing district, and (2) selected personal and professional characteristics of teachers are directly related to the number of graduate credits. After the districts were stratified according to the median salaries offered at the fifth step for the Bachelor's degree and Master's degree, the two highest incentive and the two lowest incentive districts were selected for the study from each SMSA. Hypothesis one was rejected when no significant difference was found in the number of credits attained by individual teachers in high- and low-incentive districts. The characteristics tested for hypothesis two were sex, marital status, number of children, age, teaching level, and years of experience. Only sex was found to be significantly associated with differential attainment of graduate credits, with men earning on the average 20.24 more credits than women. This difference between male and female teachers may be explained by the males' dissatisfaction with teaching and their desire to move into administration, since promotion is based on achievement of graduate credits. (HW)