A safety intervention is defined very simply as an attempt to change how things are done in order to improve safety. Within the workplace it could be any new program, practice, or initiative intended to improve safety (e.g., engineering intervention, training program, administrative procedure). Our aim in this book is to provide students, researchers and practitioners with the tools and concepts required to conduct systematic evaluations of injury prevention initiatives and safety programs. Successful evaluations will advance the discipline of occupational safety by building a body of knowledge, based on scientific evidence, that can be applied confidently in the workplace. This knowledge will provide a solid foundation for good safety practice, as well as inform the development of standards and regulations.