The document discusses using data in libraries. It introduces several presentations at a conference on needs assessment, goals, evaluation, data collection, analysis, sharing, and using data to make decisions. It then focuses on the "data trifecta" of inputs, outputs, and outcomes. Inputs refer to resources used for a program. Outputs are services and materials provided. Outcomes are the effects on participants. Considering all three provides a more complete understanding to improve programs and compare libraries. Attendees are invited to recommend projects describing how to apply the trifecta.