Resources

1. Gail MH, Altman DG, Cadarette SM, Collins G, Evans SJW, Sekula P, Williamson E, Woodward M for the STRATOS initiative (STRengthening Analytical Thinking for Observational Studies). Design choices for observational studies of the effect of exposure on disease incidence. BMJ Open 2019;9(12):e031031.

The purpose of this paper is to help readers choose an appropriate observational study design for measuring an association between an exposure and disease incidence. We discuss cohort studies, sub-samples from cohorts (case-cohort and nested case-control designs), population-based case-control studies and hospital-based case-control studies. Although these designs are well described in textbooks on epidemiology, our purpose is to introduce a broad readership to these designs and their strengths and weaknesses.

Appropriate study design is the foundation of a scientifically valid observational study to determine associations between exposures and disease. Mistakes in design are often irremediable. Key steps are understanding the scientific aims of the study and what is required to achieve them. Some designs will not yield the information required to realize the aims. The choice of design also depends on the availability of source populations and resources. Choosing an appropriate design requires balancing the pros and cons of various designs in view of study aims and practical constraints. We compare various cohort and case-control designs to estimate the effect of an exposure on disease incidence and mention how certain design features can reduce threats to study validity.

2. Gail M, Cadarette S on behalf of TG5. STRengthening Analytical Thinking for Observational Studies (STRATOS): Introducing the Study Design Topic Group (TG5). Biometric Bulletin 2019; 36(2): 12-13.

1. EQUATOR Network, Enhancing the QUAlity and Transparency Of health Research

2. Cadarette SM, Maclure M, Delaney JAC, Whitaker HJ, Hayes KN, Wang SV, Tadrous M, Gagne JJ, Consiglio GP, Hallas J. Control yourself: ISPE-endorsed guidance in the application of self-controlled study designs in pharmacoepidemiology. Pharmacoepidemiol Drug Saf 2021; 30:671-84.