3. Types of epidemiological studies

3.2 Analytic studies

3.2.2 Intervention studies

A. Experimental studies

These studies are similar to cohort studies, but the exposure (e.g. treatment) is controled by the investigator.

The advantage of this type of study is the randomization of the intervention.

Comparable groups:

  • Made up according to age, sex, weight, height, etc.

  • Are valuable to detect unknown risk factors

This type of study may raise some ethical issues, mostly related to randomization.

Example: Clinical trials most often assess the efficacy of new treatment. The investigator applies treatment to selected subjects and compares the results with those from untreated subjects.