This article investigates the utility and availability of college data to evaluate the impact of high school interventions. It reports results of a pilot study that collected information about the college experiences of graduates from four high schools in the northeast United States. Using these results as a lens, the article examines what information is available from Statewide Longitudinal Data Systems (SLDS). It identifies the contrary interactions of the development of SLDS and federal law. The article reviews the legal and practical constraints on improving the national data system, as well as possible policy changes that might improve the data environment.