The Public Impact Gap is the difference between the outcomes a government is achieving and the outcomes it could be achieving. It works by comparing a government’s performance on a given outcome (for example, road traffic safety) to a stretching but achievable benchmark based on a group of peers. A country’s Public Impact Gap tells us how far that country lags behind its peers, and also what impact could be achieved if the Gap were to be closed (for example, the number of lives that could saved). While it is a relatively simple concept, we believe that the Public Impact Gap can be a useful tool in holding governments to account for delivering outcomes in areas of fundamental importance to each of us, including education, health, and safety. Highlighting where Public Impact Gaps exist is just the beginning of the story. The Centre for Public Impact has also set out the means to diagnose, address and close Public Impact Gaps by publishing the Public Impact Fundamentals – a free tool for governments, developed with leading academics to help leaders achieve better outcomes. This tool can be used in conjunction with the Public Impact Observatory, a free database of more than 200 case studies, accessible via the Centre for Public Impact’s website.