A researcher is evaluating group counseling effectiveness using motivational interviewing for adolescents. What is the dependent variable?

In evaluating the effectiveness of group counseling using motivational interviewing for adolescents, the dependent variable is the outcome that is being measured to assess the impact of the intervention. In this case, substance use is the correct choice because it reflects the behavior or change that the researcher is most interested in observing as a result of the group counseling and motivational interviewing process.

The effectiveness of the counseling intervention is measured based on its influence on reducing or modifying adolescents' substance use behaviors, making it a key focus of assessment. The other options, such as group counseling, individual counseling, and motivational interviewing, represent facets of the intervention rather than outcomes. They describe the methods or types of counseling being implemented, but they do not serve as the specific measurement of effectiveness that the researcher is seeking.