Measuring the observer (Hawthorne) effect on adenoma detection rates

Area of Science:

• Gastroenterology
• Medical Quality Improvement
• Clinical Research Methodology

Background:

• Procedural quality in colonoscopies can be enhanced by independent observation.
• The Hawthorne effect, where individuals modify behavior when observed, may influence colonoscopy quality metrics.

Purpose of the Study:

• To evaluate the impact of an independent observer on key quality metrics during colonoscopies.
• To determine if the Hawthorne effect improves polyp, adenoma, and serrated lesion detection rates.

Main Methods:

• A single-center comparative study involving 327 patients in an index group (observed) and 360 in a reference group (unobserved).
• Quality metrics including polyp detection rate (PDR), adenoma detection rate (ADR), serrated lesion detection rate (SLDR), and advanced adenoma detection rate (AADR) were compared.
• Regression analyses weighted by the inverse probability of observation were used to evaluate metric increases.

Main Results:

• The observed group showed significantly higher PDR (62.4% vs. 53.1%) and ADR (39.4% vs. 28.3%).
• After adjustment, ADR was 50% more likely and SLDR more than twofold more likely in the observed group.
• No significant increase was observed in SLDR and AADR in the initial comparison.

Conclusions:

• The presence of an independent observer significantly increased adenoma detection rates and other colonoscopy quality metrics.
• The Hawthorne effect presents a viable, low-cost strategy for improving colonoscopy quality, comparable to advanced technologies.