We report results from our long-standing research partnership with the Massachusetts Department of Elementary and Secondary Education. We make two primary contributions. First, we illustrate the wide range of informative analyses that can be conducted using a state longitudinal data system and the advantages of examining evidence from multiple cohorts of students. Second, we document large income-based gaps in educational attainments, including high school graduation rates and college-going rates. Importantly, we show that income-related gaps in both educational credentials and academic skill have narrowed substantially over the past several years in Massachusetts.