This document discusses outcomes and how they can be used to measure the impact of library programs and services, especially teen services. It defines outcomes as benefits or changes in skill, knowledge, attitude, behavior, or life status, rather than just outputs like attendance numbers. The document recommends writing outcomes and associated measurable indicators, then evaluating programs and services using data, observations, surveys, etc. to demonstrate impact. Measuring outcomes can help justify funding, defend programs, and tell the story of how the library benefits the community.