The document presents findings from evaluating informal science education (ISE) programs, highlighting that most libraries currently do not assess long-term outcomes and rely heavily on qualitative methods. It reveals that only 17% of reports included follow-up data, suggesting a need for libraries to adopt a more comprehensive approach to evaluations, including diverse study designs and data collection methods. The Building Informal Science Education (BISE) project offers resources to help libraries enhance their evaluation practices and engage effectively with the outcomes of ISE projects.