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Identifying bias and confounding in medical papers

Fiche de révision · Anglais médical · P2

L'essentiel du cours

  1. Chapitre 1 : Bias vs. Confounding: What's the Difference?

    Bias is a flaw in the study itself; confounding is a hidden variable that distorts the true relationship.

  2. Chapitre 2 : Types of Bias You Should Know

    Selection bias affects who is in the study; information bias affects how data is measured; publication bias affects what we see in journals.

  3. Chapitre 3 : Confounding: When a Hidden Factor Interferes

    A confounder is linked to exposure and outcome but does not lie on the causal pathway; it creates a spurious association.

  4. Chapitre 4 : How to Spot Bias and Confounding in a Paper

    Always ask: Could a systematic error or a hidden variable explain these results, or is the association likely real?

Teste-toi · 8 questions

  1. 1.What is the main difference between bias and confounding?

    Voir la réponse

    Réponse : Bias is a systematic error, confounding is a third variable distorting the association

    Bias is a flaw in the study design or conduct, while confounding is caused by an external variable linked to both exposure and outcome.

  2. 2.Which of the following is an example of selection bias?

    Voir la réponse

    Réponse : A study recruiting only volunteers from a specialty clinic, who may be healthier

    Selection bias occurs when the study sample is not representative of the target population due to how participants were chosen.

  3. 3.In a study on coffee consumption and pancreatic cancer, smoking is a potential confounder because it is:

    1. A.A result of pancreatic cancer
    2. B.Associated with both coffee drinking and pancreatic cancer
    3. C.A random error in the study
    4. D.Caused by coffee consumption
    Voir la réponse

    Réponse B : Associated with both coffee drinking and pancreatic cancer

    A confounder must be associated with both the exposure (coffee) and the outcome (pancreatic cancer) but not be on the causal pathway.

  4. 4.Recall bias is classified as which type of bias?

    Voir la réponse

    Réponse : Information bias

    Recall bias is an information bias because it involves differential accuracy of reported past exposures between cases and controls.

  5. 5.Which study design is most effective at controlling for confounding?

    Voir la réponse

    Réponse : Randomized controlled trial

    Randomization evenly distributes both known and unknown confounders between groups, minimizing confounding.

  6. 6.Publication bias leads to:

    1. A.An overestimation of treatment effects in the literature
    2. B.Reduced variability between studies
    3. C.More accurate estimates of effect
    4. D.Elimination of confounding
    Voir la réponse

    Réponse A : An overestimation of treatment effects in the literature

    Because positive studies are more likely to be published, the overall literature may suggest larger effects than truly exist.

  7. 7.When reading a paper, which question helps you detect potential confounding?

    Voir la réponse

    Réponse : Did the authors adjust for variables like age and sex?

    Adjusting for potential confounders in the analysis is a key method to reduce confounding, so checking if this was done is crucial.

  8. 8.A study finds that people who take vitamin D supplements have a lower risk of multiple sclerosis. However, those who take supplements also tend to have higher income and better healthcare access. This is an example of:

    1. A.Publication bias
    2. B.Selection bias
    3. C.Recall bias
    4. D.Confounding by socioeconomic status
    Voir la réponse

    Réponse D : Confounding by socioeconomic status

    Socioeconomic status is associated with both supplement use and MS risk, so it could confound the observed association.