Which of the following characteristics apply to intervention studies?

• A. they don't require altering the behavior of study subjects, only observing them
• B. they include prevention or therapeutic trials
• C. They follow the group being studied into the future to determine risk factors
• D. They are the same as correlation studies

Answer: (B)

Intervention studies involve the researcher actively applying an intervention to participants and comparing outcomes between groups that receive the intervention and those that do not. This is true for prevention or therapeutic trials, where the goal is to see if a new program, treatment, or policy produces a measurable effect. The key is manipulation: exposure or treatment is deliberately changed, and the impact is assessed, often with randomization to reduce bias.

This differs from observational designs, where researchers simply observe without changing anything. For example, following a group over time to see who develops a condition is a prospective cohort study and analyzes natural exposure, not an assigned intervention. Correlation studies look for associations between variables but don’t involve actively changing anything to test causality; intervention studies are designed to determine whether an intervention causes a change in outcomes, typically using control groups for comparison.