Designing and undertaking randomised implementation trials: guide for researchers

Implementation science is the study of methods to promote the systematic uptake of evidence based interventions into practice and policy to improve health. Despite the need for high quality evidence from implementation research, randomised trials of implementation strategies often have serious limitations. These limitations include high risks of bias, limited use of theory, a lack of standard terminology to describe implementation strategies, narrowly focused implementation outcomes, and poor reporting. This paper aims to improve the evidence base in implementation science by providing guidance on the development, conduct, and reporting of randomised trials of implementation strategies. Established randomised trial methods from seminal texts and recent developments in implementation science were consolidated by an international group of researchers, health policy makers, and practitioners. This article provides guidance on the key components of randomised trials of implementation strategies, including articulation of trial aims, trial recruitment and retention strategies, randomised design selection, use of implementation science theory and frameworks, measures, sample size calculations, ethical review, and trial reporting. It also focuses on topics requiring special consideration or adaptation for implementation trials. We propose this guide as a resource for researchers, healthcare and public health policy makers or practitioners, research funders, and journal editors with the goal of advancing rigorous conduct and reporting of randomised trials of implementation strategies.