College student self-reported gains are used frequently in institutional research and in general research on college outcomes (Gonyea, 2005). These self-report measures serve not only to identify experiences and programs associated with student growth but also to draw comparisons across colleges and universities. The vast majority of institutions administer a national survey instrument to their students, and accreditation self-studies constitute the primary reason for conducting such institutional assessments (Kuh and Ikenberry, 2009). However, to know whether an institutionwide score reflects strong performance as opposed to a need for improvement, this score must be compared with those from other institutions. To serve as a useful indicator of student learning outcomes, self-reported gains must therefore be valid and unbiased for determining growth--and predictors of growth--both within and across institutions. This study used a large, longitudinal sample of 8,615 students at 49 colleges and universities to compare individual- and institutional-level predictors of self-reported gains and longitudinal change. Particular attention was paid to independent variables that exhibited systematic differences between longitudinal and self-reported gains across several outcomes, because consistent biases may be especially problematic in determining predictors of student learning and development. This study is the first to demonstrate that the use of self-reported gains for measuring student growth may result in consistent institution-level biases. (Contains 3 tables.)