ArticlePloS one2015
Randomization Does Not Help Much, Comparability Does.
Article in PloS one, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers, 1 of them a synthesis 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
17 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Physical Activity Reduces the Prevalence of Periodontal Disease: Systematic Review and Meta-Analysis.Frontiers in physiology · 2019Pooled it
- Online-delivered eye movement desensitization and reprocessing treatment for adults with post-traumatic stress disorder due to multiple traumas: a non-concurrent multiple baseline design.European journal of psychotraumatology · 2026Trial
- Defining blood hematology reference values in female pig-tailed macaques (Macaca nemestrina) using the Isolation Forest algorithm.Journal of medical primatology · 2024Article
- An 8-week physical exercise intervention for e'athletes improves physical performance rather than short-term esports performance parameters - a randomized controlled trial.Frontiers in sports and active living · 2024Article
- Happy and sad music acutely modulate different types of attention in older adults.Frontiers in psychology · 2023Article
- Risk of bias assessment tool for systematic review and meta-analysis of the gut microbiome.Gut microbiome (Cambridge, England) · 2023Article
- Cognitive control, bedtime patterns, and testing time in female adolescent students: behavioral and neuro-electrophysiological correlates.Frontiers in public health · 2023Article
- Reply to: "Ipragliflozin improves the hepatic outcomes of patients with diabetes with NAFLD".Hepatology communications · 2022Article
- When randomisation is not good enough: Matching groups in intervention studies.Psychonomic bulletin & review · 2021Article
- Rational, emotional, or both? Subcomponents of psychopathy predict opposing moral decisions.Behavioral sciences & the law · 2021Article
- An Immersive Investment Game to Study Human-Robot Trust.Frontiers in robotics and AI · 2021Article
- Article
- Reporting animal research: Explanation and elaboration for the ARRIVE guidelines 2.0.PLoS biology · 2020Article
- Single-Subject Research in Psychiatry: Facts and Fictions.Frontiers in psychiatry · 2020Review
- Small samples and increased variability - discussing the need for restricted types of randomization in exercise interventions in old age.European review of aging and physical activity : official journal of the European Group for Research into Elderly and Physical Activity · 2019Article
- Does sadness impair color perception? Flawed evidence and faulty methods.F1000Research · 2016Article
- Randomization Does Not Help Much, Comparability Does.PloS one · 2015Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
1 author.
Funding
No grant is acknowledged in the PubMed record.
Abstract
According to R.A. Fisher, randomization "relieves the experimenter from the anxiety of considering innumerable causes by which the data may be disturbed." Since, in particular, it is said to control for known and unknown nuisance factors that may considerably challenge the validity of a result, it has become very popular. This contribution challenges the received view. First, looking for quantitative support, we study a number of straightforward, mathematically simple models. They all demonstrate that the optimism surrounding randomization is questionable: In small to medium-sized samples, random allocation of units to treatments typically yields a considerable imbalance between the groups, i.e., confounding due to randomization is the rule rather than the exception. In the second part of this contribution, the reasoning is extended to a number of traditional arguments in favour of randomization. This discussion is rather non-technical, and sometimes touches on the rather fundamental Frequentist/Bayesian debate. However, the result of this analysis turns out to be quite similar: While the contribution of randomization remains doubtful, comparability contributes much to a compelling conclusion. Summing up, classical experimentation based on sound background theory and the systematic construction of exchangeable groups seems to be advisable.
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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.