A significant portion of U.S. secondary school students participate in summer learning programs that include mathematics learning. In order to assess the effectiveness of such programs and identify their most impactful features, there is a need to understand the long-term impact of childhood summer learning on the lives of people well into adulthood. This project focuses on a site of a mathematics-centric summer program for secondary students founded in the early 1990s that has served over 3,000 students. The study focuses on former participants over the age of 25 to examine how the program influenced both mathematics and economic outcomes years and even decades after adolescence. The investigation of long-term outcomes such as participation in STEM careers and the economic measurement of life satisfaction will provide useful insights into strengthening the STEM trajectories and informing policies aimed to influence the lives of children in and beyond their participation in educational settings. Mathematics identity, or how someone thinks about themselves in relation to the practice of mathematics, has been shown to influence career decisions and mathematics course-taking trajectories, and thus is an important focus of this investigation. Studying the mathematics identities of past program participants will provide insights into the features of the program that are linked to long-lasting mathematics-related effects of the program, offering insights that support the design and