This report is a comprehensive account of the accumulated research on the measurement of quality of effort and its significance in understanding the achievement of college students with regard to the College Student Experiences questionnaire (Pace, 1979). Results are based on the responses of 12,000 undergraduate students from 40 different colleges over a 3 year period. The questionnaire contained 14 quality of effort scales, on which students rated themselves on items concerned with the use of college facilities and the use of personal and social opportunities. The other parts of the questionnaire included items that enabled researchers to determine relationships between quality of effort and achievement and among many elements that might help to explain those relationships. A major conclusion of the study granted the importance of all elements that influence "who goes where" to college. The study also found that, once the students got to college, what counted most was not who they were or where they were but what they did. "Quality" effort appears to be what counts in achieving in college. (JM)