Question

1. 1. State the main difference between the following study designs:
   1. a. Observational and experimental studies
   2. b. Retrospective cohort and prospective cohort studies
   3. c. Cohort and case-control studies

Answer 1

Answer: Observational studies : In this type of studies the researcher collects the data by observation. The data and information is collected on the basis of the keen observation made by researcher.

Experimental studies: It involves that the collection if the data on the basis of the experiments performed by the researcher as well as the results obtained.

Retrospective cohort: In this kind of studies the researcher find out he historical data such as occurance of the disease as well as the time taken by the disease to be cured.

Prospective cohort studies: The study is performed when the time is elapsed. When there is not any occurance of the disease.

Cohort studies: This includes the studies performed as the participants are mainly evaluated for the outcome obtained for the risk factors at random time.

Case control studies: The samples from the study is selected from the cohort such as tissue sampling etc.