Table 3.

Study characteristics and findings of observational study evaluations of the Hawthorne effect

Characteristic	Campbell et al. [40]	Mangione-Smith [41]	Eckmanns et al. [42]	Leonard and Masatu [43]	Maury et al. [44]	Fox et al. [45]
Population	Paramedics	Pediatricians	Clinicians	Clinicians	Clinicians	Obstetricians
Setting	Emergency services	Community practices	Hospital intensive care units	Outpatient clinics	Hospital intensive care unit	Hospital birth unit
Operationalization of HE	Announcement of study in a memo	Impact of audio taping consultations and completing questionnaires on inappropriate antibiotic prescribing	Announcement of 10-day direct observation study of hand hygiene	Direct observation of consultations by researchers	Announcement of observational study of hand hygiene in two time periods by two clinicians	Impact of awareness of being studied on diagnostic accuracy (EFW)
Comparisons	Prior awareness-raising memo	Unobserved consultations (neither audio/questionnaire) during same time period (and also later)	Covert observational period 10 mo earlier (same research nurse observer)	Nonobserved consultations before research team arrival	Two covert observed periods (by same two clinicians) when clinicians were unaware of being observed	Accuracy of estimates found in consecutive equivalent records in an earlier period
Blinding	No	Blinded to prescribing focus, consented to communication study	Only during covert observation	No	Only during covert observation	Were aware of study of accuracy, not of HE
Outcome measure	Documentation rates of medication, allergy, and medical history	Antibiotic prescribing in viral cases by direct observation or in medical records	Observed use of AHR	Patient-reported quality of care in postconsultation questionnaire	Observed hand hygiene compliance	Differences in accuracy (proportions of EFWs at birth weight ±10%)
Sample size	145 Practitioners and 30,828 reports	10 Pediatricians. 91 Nonobserved consultations, 149 observed	2,808 Indications for AHR use, 937 in period 1 and 1,871 in period 2	Not clear	4,142 Opportunities for hand hygiene compliance in four periods (1,064, 1,045, 1,038, and 995 each)	187 in each group
Summary of reported findings	Study led to increases in 2 of 3 recording outcomes (medication and allergy, not medical history). Regression coefficients and P values reported.	Inappropriate antibiotic prescribing in viral cases was 29% lower when observed (46% vs. 17%)	AHR compliance increased from 29% to 45% during the overt observation period (OR, 2.33; 95% CI: 1.95, 2.78; higher in multivariate model)	Patient-reported quality of care increased by 13% with direct observation, and returned to preobservation levels between 10 and 15 consultations	Both observed periods saw similar increases in compliance (47-55% and 48-56%).	No differences in main analysis (67.9% vs. 68.5% control/study). Possible difference in expected direction in small subgroup of heavy babies (37% vs. 53% control/study)
Reviewer comments including on principal risks of bias	No evaluation of confounding. Differences seen after awareness-raising memo, effect may be contingent.	Information bias judged likely. Reporting complex.	Big difference in indications for use in two periods reflects different observation procedures. Observer bias also possible.	Both the analyses and the reporting of outcome data are complex.	Not a formal report, so scant detail on data collection and other study procedures.	Equivalence problematic, clinicians different in two periods, although baby characteristics similar.

Abbreviations: HE, Hawthorne effect; EFW, estimate of fetal weight; AHR, antiseptic hand rub; OR, odds ratio; CI, confidence interval.