A researcher believes that therapy is more effective if patients exercise. The researcher tells the patients that it has been arranged for them to use the hospital gym, if they so desire-and that if they are interested, they will then be in the experimental group. This represents which threat to internal validity?

Question

Quizplus · Accepted Answer

The scenario describes a situation where participants self-select into groups, which can introduce biases related to characteristics that influence their choice, thus threatening internal validity through selection bias.

A Researcher Believes That Therapy Is More Effective If Patients