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How to read a cohort study

Tata, Laila J.



Nicholas J. Talley

G. Richard Locke III

Paul Moayyedi

Yuri A. Saito


The cohort is the basis of all epidemiologic study designs as it is the closest way to study the natural progression of people's life course over which the temporal relationship between exposures and outcomes can be assessed. Although a cohort is defined as a specified group of people followed over a certain period of time, cohort studies are often used to compare the occurrence of health outcomes between groups of people with and without certain exposures or between groups with different levels of exposure. In this chapter, cohort design, analysis, and interpretation are described and summarized using a 10-point checklist of important issues to consider when reading a cohort study. This includes the potential impacts of selection bias, ascertainment bias, follow-up bias and the need to consider confounding and chance. Good understanding of cohort design provides the foundation for appraising all study designs in particular experimental trials.


Tata, L. J. (2014). How to read a cohort study. In N. J. Talley, G. Richard Locke III, P. Moayyedi, J. West, & Y. A. Saito (Eds.), GI Epidemiology: Diseases and Clinical Methodology (15-29). (Second). John Wiley & Sons, Ltd.

Online Publication Date Jan 10, 2014
Publication Date Feb 6, 2014
Deposit Date Mar 7, 2023
Pages 15-29
Edition Second
Book Title GI Epidemiology: Diseases and Clinical Methodology
Chapter Number 2
ISBN 9780470672570
Keywords epidemiology; study design; observational study; cohort study; selection bias; ascertainment bias; loss to follow-up; survival curves; time-varying exposures; aspirin; colorectal cancer
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