Fidelity monitoring in complex interventions: a case study of the WISE intervention

Researchers face many decisions in developing a measurement tool and protocol for monitoring fidelity to complex interventions. The current study uses data evaluating a nutrition education intervention, Together, We Inspire Smart Eating (WISE), in a preschool setting to explore issues of source, timing, and frequency of fidelity monitoring.

The overall study from which these data are drawn was a pre/post design with an implementation-focused process evaluation. Between 2013 and 2016, researchers monitored fidelity to evidence-based components of the WISE intervention in 49 classrooms in two Southern states. Data collectors obtained direct assessment of fidelity on a monthly basis in study classrooms. Research staff requested that educators provide indirect assessment on a weekly basis. We used mean comparisons (t-tests), correlations (Pearson's r), and scatterplots to compare the direct and indirect assessments.

No mean comparisons were statistically different. Correlations of direct and indirect assessments of the same component for the same month ranged between - 0.51 (p = 0.01) and 0.54 (p = 0.001). Scatterplots illustrate that negative correlations can be driven by individuals who are over reporting (i.e., self-report bias) and that near zero correlations approximate the ideal situation (i.e., both raters identify high fidelity).

Our findings illustrate that, on average, observed and self-reports may seem consistent despite weak correlations and individual cases of extreme over reporting by those implementing the intervention. The nature of the component to which fidelity is being monitored as well as the timing within the context of the intervention are important factors to consider when selecting the type of assessment and frequency of fidelity monitoring.

NCT03075085 Registered 20 February 2017. Trial registration corresponds to the funding that supported the writing of this manuscript, not the data collection. The original study was not a trial and was collected without registration. However, the data reported here provided foundational preliminary data for the trial.