The present study stems from the concern that recent employment trends among scientists will result in a drop in the ability of students entering scientific fields. In an attempt to provide some indication of whether such is the case, the history files of the Graduate Record Examinations were used to construct a history of aptitude test statistics for the years 1970-71 through 1974-75. The chief focus of the study was the examination of possible regular changes or trends in aptitude test mean scores over the observed period, but the study indicates that no such trends of practical significance occurred over the period. The major differences observed in scores were those between students in different fields, and these differences occurred consistently over the whole period under examination. In quantitative ability, candidates in the Sciences averaged more than one standard deviation higher than candidates in Nonscience fields and, within the Sciences, examinees in the Physical and Math Sciences averaged nearly one standard deviation higher than those in the Life and Basic Social Sciences. In verbal ability, the Science and Nonscience candidates did not differ on the average, but within the Science group, Engineering candidates averaged noticeably lower than the others. (Author)