Public libraries face a pressing need to evaluate their offerings and use the resulting evidence to inform internal decision-making. The Research Institute for Public Libraries (RIPL) has trained nearly 1,370 library staff nationwide on introductory evaluation. Califa Group - in partnership with the Colorado State Library, State Library of North Carolina, Rebecca Teasdale & Associates, LLC and LH Evaluation & Training Group - will build off RIPL's success by developing and piloting a nine-month cohort-based peer learning process to further advance evaluation skills, knowledge, and attitudes. Each cohort will evaluate a library program or service and produce empirical evidence to support internal decision-making. At least 30 public library staff members, representing 15 public libraries in three states, will complete the cohort experience. The project will also produce a library of at least 20 coaching videos that will be available for free on the project website, Infopeople platform, and the RIPL Community of Practice.