About 200 of these students were interviewed during Spring 1994. However, these students no longer represented a random sample since not all students selected agreed to participate. In the non-IMP group there was an over representation from the suburban high school (59%) and an under representation from the inner-city high school (17%). In addition, a disproportionate number of respondents (27%) had been accelerated into geometry as 9th graders. None of the IMP students were from that accelerated group when they entered high school. Given the profile of the non-IMP students responding, that group could not be used as a valid control group to measure achievement in college