SynthesisBulletin of the World Health Organization2015
Participants' understanding of informed consent in clinical trials over three decades: systematic review and meta-analysis.
Synthesis in Bulletin of the World Health Organization, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 143 papers, 7 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
143 citing papers in PubMed, 7 syntheses or guidelines pooled it.
- Measuring and evaluating participant understanding of consent processes in clinical trials: a systematic review.Trials · 2026Pooled it
- Participants' understanding of informed consent in clinical trials: A systematic review and updated meta-analysis.PloS one · 2024Pooled it
- Pooled it
- Ethical Aspects of Personalized Research and Management of Systemic Inflammatory Response Syndrome (SIRS) in Children.International journal of environmental research and public health · 2022Pooled it
- Digital tools in the informed consent process: a systematic review.BMC medical ethics · 2021Pooled it
- The reality of informed consent: empirical studies on patient comprehension-systematic review.Trials · 2021Pooled it
- Informed consent and ethical reporting of research in clinical trials involving participants with psychotic disorders.Contemporary clinical trials · 2019Pooled it
- Effectiveness of Telehealth Versus In-Person Informed Consent: Randomized Study of Comprehension and Decision-Making.Journal of medical Internet research · 2025Trial
- Patients' perceptions and practices of informing relatives: a qualitative study within a randomised trial on healthcare-assisted risk disclosure.European journal of human genetics : EJHG · 2024Trial
- Opportunistic screening for COPD among socially marginalized patients.BMC pulmonary medicine · 2024Trial
- Trial
- House screening for malaria control: views and experiences of participants in the RooPfs trial.Malaria journal · 2022Trial
- Remote consent approaches for mobile phone surveys of non-communicable disease risk factors in Colombia and Uganda: A randomized study.PloS one · 2022Trial
- Examining study participants' decision-making and ethics-related experiences in a dietary community randomized controlled trial in Malawi.BMC medical ethics · 2021Trial
- Patient understanding and acceptability of an early lung cancer diagnosis trial: a qualitative study.Trials · 2018Trial
- Assessing informed consent in an opioid relapse prevention study with adults under current or recent criminal justice supervision.Journal of substance abuse treatment · 2017Trial
- Improved participants' understanding of research information in real settings using the SIDCER informed consent form: a randomized-controlled informed consent study nested with eight clinical trials.European journal of clinical pharmacology · 2017Trial
- Decision Aids Can Support Cancer Clinical Trials Decisions: Results of a Randomized Trial.The oncologist · 2016Trial
- Getting It "Right".Journal of empirical research on human research ethics : JERHRE · 2016Trial
- Trial
83 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.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo estimate the proportion of participants in clinical trials who understand different components of informed consent.
methodsRelevant studies were identified by a systematic review of PubMed, Scopus and Google Scholar and by manually reviewing reference lists for publications up to October 2013. A meta-analysis of study results was performed using a random-effects model to take account of heterogeneity.
findingsThe analysis included 103 studies evaluating 135 cohorts of participants. The pooled proportion of participants who understood components of informed consent was 75.8% for freedom to withdraw at any time, 74.7% for the nature of study, 74.7% for the voluntary nature of participation, 74.0% for potential benefits, 69.6% for the study's purpose, 67.0% for potential risks and side-effects, 66.2% for confidentiality, 64.1% for the availability of alternative treatment if withdrawn, 62.9% for knowing that treatments were being compared, 53.3% for placebo and 52.1% for randomization. Most participants, 62.4%, had no therapeutic misconceptions and 54.9% could name at least one risk. Subgroup and meta-regression analyses identified covariates, such as age, educational level, critical illness, the study phase and location, that significantly affected understanding and indicated that the proportion of participants who understood informed consent had not increased over 30 years.
conclusionThe proportion of participants in clinical trials who understood different components of informed consent varied from 52.1% to 75.8%. Investigators could do more to help participants achieve a complete understanding.
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.