Intervention Fidelity: Monitoring Drift, Providing Feedback, and Assessing the Control Condition

Measurement of intervention fidelity is an essential component of any scientifically sound intervention trial. However, few papers have proposed ways to integrate intervention fidelity data into the execution of these trials.

The purpose of this article is to describe the intervention fidelity process used in a randomized controlled trial of a human patient simulator intervention and how these data were used to monitor drift and provide feedback to improve the consistency of both intervention and control delivery over time in a multisite education intervention for parents of children with newly diagnosed Type 1 diabetes.

Intervention fidelity was measured for both the intervention and control condition by direct observation, self-report of interventionist delivery, and parent participant receipt of educational information. Intervention fidelity data were analyzed after 50%, 75%, and 100% of the participants had been recruited and compared by group (treatment and control) and research site.

The sample included 191 parents of young children newly diagnosed with Type 1 diabetes. Observations scores in both intervention and control groups indicated a high level of intervention fidelity. Treatment receipt was also high and did not differ by treatment group. The teaching session attendance rates by site and session were significantly different at Time Point 1 (50% enrollment); following study staff retraining and reinforcement, there were no significant differences at Time Point 3 (100% enrollment).

Results demonstrate the importance of monitoring intervention fidelity in both the intervention and control condition over time and using these data to correct drift during the course of a multisite clinical trial.