The 'Hawthorne effect' in clinical trials refers to:

• A Improvement in the control group due to placebo administration
• B Regression to the mean in extreme baseline values
• C Differential loss to follow-up between trial arms
• D Behavioural change in participants caused by the awareness of being observed ✓

Explanation

The Hawthorne effect describes the modification of behaviour by study participants simply because they know they are being observed or studied, independent of any specific intervention. This can inflate the apparent efficacy of any intervention. Regression to the mean is a statistical phenomenon affecting repeat measurements. Differential attrition is informative censoring, a separate bias type.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.