ArticleEmerging themes in epidemiology2008
The role of causal reasoning in understanding Simpson's paradox, Lord's paradox, and the suppression effect: covariate selection in the analysis of observational studies.
Article in Emerging themes in epidemiology, 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 27 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
27 citing papers in PubMed, 1 synthesis or guideline pooled it.
- The Same but Different?: A Systematic Review of the Impact of Selection and Collider Bias on Internal Validity.Epidemiology (Cambridge, Mass.) · 2025Pooled it
- Illusions of Understanding in the Sciences.Computational brain & behavior · 2026Article
- Incidence and predictors of complications of tube thoracostomy performed in the emergency department for non-traumatic pleural pathologies.Internal and emergency medicine · 2026Article
- Ten quick tips for causal analysis of biomedical omics data.PLoS computational biology · 2026Article
- Postresuscitation platelet transfusion in major trauma patients.Transfusion · 2025Article
- The Where and the Why of Obstructive Sleep Apnea.Annals of the American Thoracic Society · 2025Article
- Thrombocytopenia in critically ill trauma patients is associated with the pattern and duration of postinjury organ dysfunction.Research and practice in thrombosis and haemostasis · 2025Article
- Cerebellar grey matter volume is associated with semantic fluency performance in amyotrophic lateral sclerosis patients.Brain communications · 2025Article
- Influenza vaccination patterns among at-risk patients during the Covid-19 pandemic-a retrospective cross-sectional study based on claims data.Infection · 2024Article
- Comment on Calugi et al. The Role of Weight Suppression in Intensive Enhanced Cognitive Behavioral Therapy for Adolescents with Anorexia Nervosa: A Longitudinal Study.International journal of environmental research and public health · 2023Article
- Antenatal Programming of Hypertension: Paradigms, Paradoxes, and How We Move Forward.Current hypertension reports · 2022Review
- Leveraging vibration of effects analysis for robust discovery in observational biomedical data science.PLoS biology · 2021Article
- Underlying Medical Conditions Associated With Severe COVID-19 Illness Among Children.JAMA network open · 2021Article
- A causal inference perspective on the analysis of compositional data.International journal of epidemiology · 2020Article
- Pooling Different Safety Data Sources: Impact of Combining Solicited and Spontaneous Reports on Signal Detection In Pharmacovigilance.Drug safety · 2019Article
- Risk factors for recurrent macrosomia and child outcomes.World journal of pediatrics : WJP · 2019Article
- Commentary: Tobacco smoking and asthma: multigenerational effects, epigenetics and multilevel causal mediation analysis.International journal of epidemiology · 2018Article
- Risk ratios for contagious outcomes.Journal of the Royal Society, Interface · 2018Article
- Prediction of Long-term Cognitive Decline Following Postoperative Delirium in Older Adults.The journals of gerontology. Series A, Biological sciences and medical sciences · 2017Article
- Article
Corrections and comments
- Comment on
Authors and funding
1 author.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Tu et al present an analysis of the equivalence of three paradoxes, namely, Simpson's, Lord's, and the suppression phenomena. They conclude that all three simply reiterate the occurrence of a change in the association of any two variables when a third variable is statistically controlled for. This is not surprising because reversal or change in magnitude is common in conditional analysis. At the heart of the phenomenon of change in magnitude, with or without reversal of effect estimate, is the question of which to use: the unadjusted (combined table) or adjusted (sub-table) estimate. Hence, Simpson's paradox and related phenomena are a problem of covariate selection and adjustment (when to adjust or not) in the causal analysis of non-experimental data. It cannot be overemphasized that although these paradoxes reveal the perils of using statistical criteria to guide causal analysis, they hold neither the explanations of the phenomenon they depict nor the pointers on how to avoid them. The explanations and solutions lie in causal reasoning which relies on background knowledge, not statistical criteria.
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.