Biodiversity offsets are conservation tool used by governments and developers to mitigate the impacts of development and infrastructure projects on biodiversity. While the use of use of offsetting policies and projects has rapidly increased worldwide, with more than 122 policies now existing across more than 100 countries, their effectiveness in achieving their goal of no-net-loss of biodiversity remains uncertain. Our research uses multiple methods (including statistical modelling and policy reviews) to determine the effectiveness of offsetting projects and how policy changes can improve outcomes for biodiversity and people.