Systematic review of the Hawthorne effect: New concepts are needed to study research participation effects

• Published in: Journal of clinical epidemiology Vol. 67; no. 3; pp. 267 - 277
• Main Authors: McCambridge, Jim, Witton, John, Elbourne, Diana R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.2014; Elsevier; Elsevier Limited
• Subjects: Analysis. Health state; Assessment; Behavior; Bias; Biological and medical sciences; Design; Emotions; Epidemiology; General aspects; Hawthorne effect; Human Experimentation; Humans; Internal Medicine; Mediation; Medical sciences; Methodology; Observation; Public health. Hygiene; Public health. Hygiene-occupational medicine; Randomized Controlled Trials as Topic - psychology; Reactivity; Research Design; Research methods; Research participation; Research Subjects - psychology; Review; Studies; Research participation; Observation; Hawthorne effect; Reactivity; Assessment; Research methods; Concept; Human; Participation; Methodology; Evidence-based practice; Systematic review; Method; Epidemiology; Evidence-based medicine; Need; Scientific research; Bibliographic review; Public health
• ISSN: 0895-4356; 1878-5921; 1878-5921
• DOI: 10.1016/j.jclinepi.2013.08.015

This study aims to (1) elucidate whether the Hawthorne effect exists, (2) explore under what conditions, and (3) estimate the size of any such effect. This systematic review summarizes and evaluates the strength of available evidence on the Hawthorne effect. An inclusive definition of any form of research artifact on behavior using this label, and without cointerventions, was adopted. Nineteen purposively designed studies were included, providing quantitative data on the size of the effect in eight randomized controlled trials, five quasiexperimental studies, and six observational evaluations of reporting on one's behavior by answering questions or being directly observed and being aware of being studied. Although all but one study was undertaken within health sciences, study methods, contexts, and findings were highly heterogeneous. Most studies reported some evidence of an effect, although significant biases are judged likely because of the complexity of the evaluation object. Consequences of research participation for behaviors being investigated do exist, although little can be securely known about the conditions under which they operate, their mechanisms of effects, or their magnitudes. New concepts are needed to guide empirical studies.