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Review
. 2003 Jan;20(1):54-60.
doi: 10.1136/emj.20.1.54.

Observational research methods. Research design II: cohort, cross sectional, and case-control studies

C J Mann  1
Affiliations
Review

Observational research methods. Research design II: cohort, cross sectional, and case-control studies

C J Mann. Emerg Med J. 2003 Jan.

Abstract

Cohort, cross sectional, and case-control studies are collectively referred to as observational studies. Often these studies are the only practicable method of studying various problems, for example, studies of aetiology, instances where a randomised controlled trial might be unethical, or if the condition to be studied is rare. Cohort studies are used to study incidence, causes, and prognosis. Because they measure events in chronological order they can be used to distinguish between cause and effect. Cross sectional studies are used to determine prevalence. They are relatively quick and easy but do not permit distinction between cause and effect. Case controlled studies compare groups retrospectively. They seek to identify possible predictors of outcome and are useful for studying rare diseases or outcomes. They are often used to generate hypotheses that can then be studied via prospective cohort or other studies.

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References

    1. BMJ. 1998 May 30;316(7145):1636-42 - PubMed
    1. BMJ. 1998 May 30;316(7145):1643-6 - PubMed
    1. BMJ. 1998 Jun 13;316(7147):1784-5 - PubMed
    1. Dev Med Child Neurol. 1971 Feb;13(1):9-14 - PubMed
    1. BMJ. 1998 May 30;316(7145):1631-5 - PubMed