"This report introduces systematic reviews of the literature as a research methodology to summarize the existing evidence with a transparent, reliable, and valid approach. It covers the systematic review steps: (1) define the question, (2) create a protocol, (3) conduct a literature search and screen for inclusion, (4) document and assess included studies, and (5) evaluate and interpret the body of evidence. The report also provides resources for drawing conclusions and developing recommendations based on the systematic review. We performed a literature review and consulted with producers and consumers of systematic reviews over the course of the project to identify available resources. National Institute for Occupational Safety and Health (NIOSH) staff provided a draft systematic review framework and continuous input to ensure relevance and applicability to occupational safety and health questions. The report draws on key general existing guidance for systematic reviews as well as identified resources specific to occupational safety and health evidence synthesis. Occupational safety and health is an extensive multidisciplinary field and encompasses a broad spectrum of issues that affect the health and safety of individuals in the workplace. Standard systematic review tools and methods may need to be adapted to fit the unique requirements of evidence synthesis for occupational safety and health questions. The report provides practical guidance to execute a systematic review as well as considerations specific to evidence synthesis for occupational safety and health questions"--Publisher's description.