'Perimeter Institute for Theoretical Physics (Perimeter) is an independent, resident-based research institute that supports scientific research, training and educational outreach in foundational theoretical physics. Founded in 1999, Perimeter’s mission is to advance the understanding of the universe at the most fundamental level, stimulating breakthroughs that could transform our future. The purpose of this evaluation was to assess the relevance and performance of Perimeter. The evaluation covered the period from April 2012 to December 2016 and expanded on the June 2016 third-party evaluation Perimeter undertook in accordance with its funding agreement. The evaluation employed four primary data collection methods including a document review, literature review, interviews and operational benchmarking”--Executive summary, p. ii.