Systematic review of the Hawthorne effect: New concepts are needed to study research participation effects
McCambridge, Witton and Elbourne systematically reviewed the Hawthorne effect and included nineteen studies: eight randomised controlled trials, five quasi-experimental studies and six observational evaluations, all but one in the health sciences. Most showed some evidence of an effect, but methods, settings and findings varied widely and the authors judged that significant biases were likely. They concluded that research participation affects the behaviours studied while little is known about when, how or how much, and they proposed research participation effects as a starting concept and suggested the unqualified term be abandoned.
McCambridge, Witton and Elbourne systematically reviewed the Hawthorne effect and included nineteen studies: eight randomised controlled trials, five quasi-experimental studies and six observational evaluations, all but one in the health sciences. Most showed some evidence of an effect, but methods, settings and findings varied widely and the authors judged that significant biases were likely. They concluded that research participation affects the behaviours studied while little is known about when, how or how much, and they proposed research participation effects as a starting concept and suggested the unqualified term be abandoned.
Written from the abstract and discussion, PubMed Central PMC3969247 (first 100,000 characters read), 2026-11-02.
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McCambridge, J., Witton, J., & Elbourne, D. R. (2014). Systematic review of the Hawthorne effect: New concepts are needed to study research participation effects. Journal of Clinical Epidemiology, 67(3), 267-277. doi:10.1016/j.jclinepi.2013.08.015 https://doi.org/10.1016/j.jclinepi.2013.08.015