This document discusses strategies for school librarians to measure the impact of school libraries on student learning outcomes through evidence-based practice. It recommends that school librarians develop the capacity to collect and articulate needs based on both formal research evidence and local evidence gathered in their own schools. Various tools and methods are presented for school librarians to gather, analyze, and report both quantitative and qualitative evidence on the contributions of the school library to student learning. These include measures of student writing skills, search behaviors, feedback surveys, classroom observations, and case studies featuring students' own voices.