The second column of the table shows response rate differentials by stratum. This is due primarily to the fact that a larger share of this stratum was not enrolled in the spring semester. The table on the next page shows completion rates by characteristics of students. Completion rates were lower for seniors, particularly L and S seniors, than for under-class students, reflecting the fact that a significant minority of seniors had already graduated and left Madison. Those not registered at the time the sample was drawn in December have very low completion rates for the same reason.
Women are somewhat more likely to participate than men.
There are only small differences by ethnic group. Higher GPA students are more likely to participate than students with GPA s of less than 3.0. The mean length of the interview was 23.0 minutes. The median was 22 minutes. Less than 10 percent of the interviews took 30 minutes or longer.