Certain advantages and disadvantages exist for each of the various study designs. Compare and contrast the advantages and disadvantages of case control and cohort study designs (15 marks).
Comment: In this case, we give advantages and disadvantages of cohort and case control study designs and offer a summary table to bring out their strengths and shortcomings.
1. Allow complete information on the subject’s exposure, including quality control of data, and experience thereafter.
2. Provide a clear temporal sequence of exposure and disease.
3. Give an opportunity to study multiple outcomes related to a specific exposure.
4. Permit calculation of incidence rates ...view middle of the document...
2. Validation of information on exposure is difficult, or incomplete, or even impossible.
3. By definition, concerned with one disease only.
4. Cannot usually provide information on incidence rates of disease.
5. Generally incomplete control of extraneous variables.
6. Choice of appropriate control group may be difficult.
Comparison of strengths and weaknesses of cohort and case control studies
Characteristics Cohort studies Case control studies
Suited for rare diseases No Yes since starting with a set of cases
Suited for rare exposures Yes since starting with exposure status No
Allows for studying several exposures Difficult but examples exists
(Framingham study) Yes
Allows for studying several outcomes Yes No
Disease status easy to ascertain Sometimes difficult Easier since starting point of the study
Exposure status easier to ascertain Yes since starting point of the study.
Except for retrospective cohorts Sometimes difficult.
Allows computation of risk and rates Yes No
Allows computation of effect...