Identify an appropriate analysis for case series crosssectio
Identify an appropriate analysis for case series, cross-sectional, and case-control studies.
Solution
Case Series - A study of multiple occurrences of unusual cases that have similar characteristics. Investigators can calculate the frequency of symptoms or characteristics of people with the disease. Results may generate causal hypotheses. Neither a case study nor a case series includes a comparison group. Cross-Sectional Study - A study with individual-level variables that measures exposure and disease at one point in time. A snapshot of the study population. This study design provides weak evidence of causal assocation between exposure and outcome because the exposure may not have preceded the disease. A patient survey is an example of a cross-sectional study. Case-Control Study -A study that identifies individuals who develop the disease (cases) and individuals without the disease (controls), and then determines the previous exposure of both cases and controls. The case group is composed only of individuals known to have the outcome; the control group is drawn from a comparable population who have not experienced the outcome. We compare the odds of exposure between cases and controls. A case-control study is stronger than a cross-sectional study in establishing individual-level causality because we are certain that exposure preceded the disease outcome. The association is reported as an odds ratio.