The limited extent to which research evidence is utilised in healthcare and other public services is widely acknowledged. The United Kingdom government has attempted to address this gap by funding nine Collaborations for Leadership in Applied Health Research and Care (CLAHRCs). CLAHRCs aim to carry out health research, implement research findings in local healthcare organisations and build capacity across organisations for generating and using evidence. This wide-ranging brief requires multifaceted approaches; assessing CLAHRCs' success thus poses challenges for evaluation. This paper discusses these challenges in relation to seven CLAHRC evaluations, eliciting implications and suggestions for others evaluating similarly complex interventions with diverse objectives.