The effect of verbal and numerical reasoning and effort level on achievement of students in an undergraduate Test and Measurement course was investigated. Course achievement was measured by a teacher-made test of 40 items that produced a mean of 21.33 and a standard deviation of 6.73. The ability scores of the 24 students (Chamorros, Filipinos and Statesiders) on a test of 25 items covering numerical reasoning and verbal reasoning correlated with achievement scores with a coefficient of .77 and the self-ratings on effort with achievement scores with a coefficient of .53. It was found that low-ability students in the sample exerted less effort than the high-ability students and, therefore, that both ability and effort had a depressing effect on the achievement of low-ability students. Reasoning ability was found to be about 5 times more important than effort in achievement. Contains 5 references. (KM)