Complex interventions targeted at sustaining independence for older people with frailty are traditionally evaluated through the ‘gold standard’ methodology of randomised controlled trials (RCT). However, it is becoming more widely appreciated that standard trial methodology for evaluating complex interventions has its limitations within this setting, and more appropriate or novel methods are therefore required to enable efficient evaluation.

We will begin by identifying the documented methodological challenges that have arisen in the evaluation of such interventions within this setting, before developing strategies to address some of these challenges, and highlighting gaps for future research.