Which statement best describes the nature of intervention studies?

• A. They do not require altering behavior of participants
• B. They include prevention or therapeutic trials
• C. They follow groups forward in time to determine risk factors
• D. They are the same as correlation studies

Answer: (B)

Intervention studies involve researchers actively implementing an intervention and measuring its effects, usually with a comparison group. This includes prevention or therapeutic trials where participants are exposed to a treatment, program, or policy and outcomes are compared to those who do not receive the intervention or receive a different one. The key idea is deliberate manipulation by investigators to assess causality, rather than just observing what happens naturally. This is different from observational designs, like prospective studies that follow people over time to identify risk factors without assigning any treatment, and from correlation studies that look for relationships between variables without any experimental manipulation.