What is a placebo and why is it used in experiments?

• A. A placebo is a drug with active ingredients given to the control group.
• B. A placebo is an inert substance or condition used as a control to account for expectations and placebo effects that can influence outcomes.
• C. A placebo is a randomization procedure.
• D. A placebo is a statistical technique to adjust outcomes.

Answer: (B)

A placebo is an inert substance or condition given to participants that resembles the real treatment but has no active therapeutic ingredients. It’s used as a control to account for expectations and placebo effects—the improvements or changes that come from believing you’re being treated—so researchers can tell whether outcomes are due to the actual treatment or to psychological factors. By comparing results from the active treatment group with the placebo group, we can isolate the true effect of the treatment. In good experiments, blinding helps prevent bias so neither participants nor researchers influence the results. The other options mix up different concepts: a placebo isn’t an active drug, it isn’t a randomization procedure, and it isn’t a statistical technique.