The Health Foundation’s programme to explore whether social franchising might support the effective spread and scale of well-evidenced interventions in the NHS offers an exciting opportunity to investigate the potential benefits of an innovative approach to scale and spread.

Alongside our partners, the Innovation Unit, we’ve been working closely with the Health Foundation to develop a flexible yet robust approach to evaluating the programme. The Health Foundation’s Sarah Henderson explore the challenges of evaluating an “ever-changing experiment”, and the approaches we’ve developed collaboratively to overcome these challenges, in this article.