Which term best defines the evaluation of an intervention's effectiveness?

The term that best defines the evaluation of an intervention's effectiveness is "Assessment." This term encompasses the systematic process of collecting, reviewing, and using information to evaluate an intervention's performance and outcomes. Assessment not only involves measuring the effectiveness of an intervention but also typically includes determining whether goals were met and identifying areas for improvement.

In contrast, "Analysis" often refers to the examination of data or information, which can be part of an assessment but does not specifically address the evaluation of effectiveness. "Response" generally refers to actions taken as a result of findings, which is a phase that follows assessment. "Planning" involves outlining steps for future actions or interventions, which is proactive rather than retrospective and evaluative like assessment. Therefore, the most accurate term related to evaluating the effectiveness of an intervention is assessment.