SynthesisFrontiers in medicine2022
Defining and evaluating the Hawthorne effect in primary care, a systematic review and meta-analysis.
Synthesis in Frontiers in medicine, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 68 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
68 citing papers in PubMed, 3 syntheses or guidelines pooled it, 110 citations in OpenAlex.
- Systematic literature review of economic studies on nature-based social prescribing for health improvement.BMC primary care · 2026Pooled it
- Evaluating the impact of video cameras on participant behaviour in research: a systematic review and meta-analysis.Systematic reviews · 2026Pooled it
- Health risk behaviours, mental health and HbA1c: an overview of reviews of observational studies.BMJ open · 2025Pooled it
- Impact of the EILA application on smoking cessation among hospital workers: a randomised controlled trial.Occupational and environmental medicine · 2026Trial
- One-year impact on HPV vaccination coverage of a school- and primary care-based intervention: the PrevHPV cluster randomised trial.Scientific reports · 2026Trial
- Efficacy of probiotic supplementation in reducing primary dysmenorrhea: a double-blinded randomized controlled trial.Scientific reports · 2026Trial
- Adherence, Acceptability, and Sexual Health Outcomes of the Odeya App-Based Intervention for Sexual Distress in Women With Endometriosis: Randomized Controlled Mixed Methods Trial.Journal of medical Internet research · 2026Trial
- Effects of antidepressant medications on brain tissue microstructure in persistent depressive disorder across two randomized controlled trials.NeuroImage. Clinical · 2026Trial
- The Feasibility and Acceptability of an App-Based Intervention Aimed at Improving Maternal Health Literacy Regarding Infant Play and Development: Mixed Methods Study.JMIR formative research · 2025Trial
- Exercise therapy and self-management support for individuals with multimorbidity: a randomized and controlled trial.Nature medicine · 2025Trial
- Short-term efficacy of peripheral nerve stimulation for essential tremor in a randomized double-blind controlled trial.Scientific reports · 2025Trial
- Non-surgical periodontal therapy with and without hyaluronic acid gel in type 2 diabetic stage-II periodontitis patients: a randomized clinical trial.BMC oral health · 2025Trial
- Assessing the adherence and acceptability to iron and folic acid compared with multiple micronutrient supplements during pregnancy: a cluster-randomized noninferiority trial in Cambodia.The American journal of clinical nutrition · 2025Trial
- The participation in cervical cancer screening is not altered by the Hawthorne effect among patients of doctors participating in the randomized clinical trial PaCUDAHL.BMC research notes · 2025Trial
- Peer Navigation for Smoking Cessation in People With HIV Who Smoke: A Pilot Randomized Controlled Trial.Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco · 2025Trial
- Trial
- Impact of provision of abdominal aortic calcification results on fruit and vegetable intake: 12-week randomized phase 2 controlled trial.Nature communications · 2024Trial
- Trial
- Psychosocial, Mental, and Suboptimal Health Measures Are Not Affected by Provision of Abdominal Aortic Calcification Imaging Results: A 12-Week RCT.AJPM focus · 2026Article
- [Pioneering trials in ophthalmology-From clinical trials to guideline treatment].Die Ophthalmologie · 2026Article
8 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
In 2015, we conducted a randomized controlled trial (RCT) in primary care to evaluate if posters and pamphlets dispensed in general practice waiting rooms enhanced vaccination uptake for seasonal influenza. Unexpectedly, vaccination uptake rose in both arms of the RCT whereas public health data indicated a decrease. We wondered if the design of the trial had led to a Hawthorne effect (HE). Searching the literature, we noticed that the definition of the HE was unclear if stated. Our objectives were to refine a definition of the HE for primary care, to evaluate its size, and to draw consequences for primary care research. We designed a Preferred Reporting Items for Systematic reviews and Meta-Analyses review and meta-analysis between January 2012 and March 2022. We included original reports defining the HE and reports measuring it without setting limitations. Definitions of the HE were collected and summarized. Main published outcomes were extracted and measures were analyzed to evaluate odds ratios (ORs) in primary care. The search led to 180 records, reduced on review to 74 for definition and 15 for quantification. Our definition of HE is "an aware or unconscious complex behavior change in a study environment, related to the complex interaction of four biases affecting the study subjects and investigators: selection bias, commitment and congruence bias, conformity and social desirability bias and observation and measurement bias." Its size varies in time and depends on the education and professional position of the investigators and subjects, the study environment, and the outcome. There are overlap areas between the HE, placebo effect, and regression to the mean. In binary outcomes, the overall OR of the HE computed in primary care was 1.41 (95% CI: [1.13; 1.75];
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.