The validity and reliability of aggregating individuals' perceptions of college organizational characteristics to more macro units of analysis were examined. The focus was the extent to which data collected in a national study met the internal consistency criterion for aggregating perceptual data to the institution level. The study assessed key dimensions of institutional performance and effectiveness. Respondents were to take an institutional rather than an individual focus. For 334 participating colleges and universities, responses were obtained from 3,406 administrators, faculty, and trustees. The results argue against aggregating individual perceptions of college conditions. Organizational climate scores derived by averaging individuals' perceptions of conditions do not reflect how individuals in an organization generally perceive, understand, or respond to organizational conditions. The results suggest that employing group means to draw conclusions about organizational conditions may lead to spurious conclusions, and that previous studies in higher education that draw conclusions based on aggregated perceptual data may be seriously flawed. The questionnaire used in the national study is appended. (SW)