In epidemiology, study mainly deals only with the distribution of diseases/conditions in human and with the factors influencing the distribution and the frequency of diseases. Study design can be mainly classified into two types,
Observational study design and Experimental study design.
The reason to conduct studies is:(1)
- To describe the burden, severity, prevalence of the disease, risk factors and health behaviors that increases the risk of disease.
- To determine how effective the intervention is.
Observational Studies: In these types of study the investigator observes the occurrence of the disease in population groups that are exposed to some exposure. These studies are representative of the target
population. Cohort, cross-sectional and case control studies are collectively referred to as observational
Experimental studies: This study design is more powerful than other study designs. In this design, investigators
control over the allocation of exposure, its associated factors and observation of the outcome(3).
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