On the basis of two reports by the Comptroller and Auditor General, we took evidence from HM Treasury, the Finance Function, the Analysis Function and the Evaluation Task Force about the use of evaluation and modelling across government.1 Cabinet Office introduced cross-government ‘functions’ in 2013 to provide professional support to departments. HM Treasury has overall responsibility for the Finance Function, and the UK Statistics Authority is responsible for the Analysis Function. The Evaluation Task Force, a joint HM Treasury and Cabinet Office Unit, was set up in April 2021 to “deliver a step-change in the scale, quality and impact of evaluation practice in government”.