PUB 540 Describe the common characteristics and design of a case-control study Re: Topic 6 DQ 1

Case-control studies allow the investigator to measure exposure and outcome to study the outcome variables for both case and control.  Then the association between the control group and case groups are compared for similarities.  There are key selection criteria features when using this type of design. These are the key features as discussed by Setia (2016): 1) Case must be clearly well described to include all aspects of the selection criterion; 2) they need to come from the same group and the evaluation methods must be the same for both case and control group; 3) Matching can be used to ensure the case group and control group would be the same, for example with smokers, selection of the same age group and gender helps. One freedom is that where cases are collected is not a constraint.  Cases and control groups can come from clinics, hospitals, or medical registrars according to Kumar (n.d.).  All these factors mentioned are crucial as not create selection bias as also discussed by Setia (2016).

Case control studies are usually retrospective according to Kumar (n.d.), so selection bias can occur easily.  When selection bias occurs, it opens the door to groups that should be compared because the similarities may not be there.  And, if hospital cases are chosen, patients with higher exposure could produce skewed results.

References

Kumar (n.d.) Introduction to Study Designs – Case-Control Studies.  Health Knowledge Website. https://www.healthknowledge.org.uk/e-learning/epidemiology/practioners/introduction-study-design-ccs

Setia M. S. (2016). Methodology Series Module 2: Case-control Studies. Indian journal of dermatology, 61(2), 146–151. https://doi.org/10.4103/0019-5154.177773