Validity of hand antisepsis adherence observations as a method for measuring and improving adherence – quantifying and visualizing the Hawthorne effect

Aim: Evaluate how well hand antisepsis adherence observations measure or increase adherence. Method: A prospective observational study using double-blinded Wi-Fi-based dispenser recordings and overt adherence observations was conducted in an intensive care unit at a German university teaching hospital. The study was part of a multimodal approach aimed at improving hand hygiene. During the six-week study period, Wi-Fi hand sanitizers recorded every hand antisepsis event in each room. A highly trained health science student conducted ten standardized, non-covert observation sessions in selected ICU rooms, each lasting two and a half hours. Results: A total of 3,957 hand antisepsis events were recorded. A Student’s t-test revealed significant differences in the number of hand antisepsis events per patient during adherence monitoring compared to days without observations. Observed adherence was 70%. The Hawthorne effect was quantified and showed that observed adherence must be reduced by approximately 24% to determine real, uninfluenced adherence, which was 53%. As soon as adherence monitoring begins, adherence levels rise, and immediately after monitoring ends, they drop back down to exactly the same level as before. Adherence observations had much less influence on the amount of hand sanitizer used. Conclusions: With Wi-Fi recording of hand sanitization events, the transient Hawthorne effect during hand hygiene adherence observations and real, everyday adherence could be quantified. The results showed that even with a multimodal approach that included adherence monitoring and feedback, no further improvement could be achieved in a hospital that had been focusing on hand hygiene for many years.