What does the term 'baseline' refer to in experimental design?

The term 'baseline' in experimental design refers specifically to the measured rate of behavior prior to any intervention. Establishing a baseline is crucial as it provides a point of comparison for assessing the effects of the intervention. By measuring the target behavior before any changes are introduced, researchers can determine whether subsequent interventions have had a significant impact.

Having a clear baseline allows therapists and researchers to track changes, evaluate the effectiveness of interventions, and analyze patterns in behavior over time. This initial measurement helps to ensure that any observed changes can be attributed to the intervention rather than to external factors or natural fluctuations in behavior.

In contrast to this, the other options describe different aspects of the evaluation process but do not capture the essence of what a baseline is. The period after an intervention starts refers to the phase where changes are implemented, while the average result of multiple interventions pertains to overall effectiveness but doesn't provide initial context. The final outcome after an intervention has ended indicates the results but is more about conclusions drawn after the fact, rather than the foundational measurements necessary at the start of an experimental phase.