Value of small sample sizes in rapid-cycle quality improvement projects 2: assessing fidelity of implementation for improvement interventions

The following are our take home points: 1. It is essential to ensure high fidelity during early implementation prior to broader dissemination and evaluation. 2. We propose five steps to measuring fidelity during early implementation. – choose a fidelity measure based on a change theory – establish a minimum acceptable fidelity – establish a sampling strategy – choose a practical sample size – create a run chart. 3. We suggest three measurement milestones during early implementation: – two consecutive convenience samples above minimum acceptable fidelity – two consecutive purposive samples above minimum acceptable fidelity – one run chart of 10 purposive samples, each with at least 10 observations, showing stable implementation with median value above the minimum acceptable fidelity. © Article author(s).