This essay evaluates the scientific quality of two studies of campus diversity. Both gained prominence prior to the Supreme Court's 2003 Grutter v. Bollinger and Gratz v. Bollinger decisions. Using different data and different research designs, the studies reached contrary conclusions about the efficacy of campus diversity. The evaluation centers on conception formation, the reliability of measures, nested data and level of analysis, the demonstration of cause and effect, and the appropriateness of certain types of survey questions. One study generally fares better than the other in terms of these scientific considerations, although many interesting and formidable challenges to the study of campus diversity remain.