What type of assessment aims to understand the function of a behavior during its occurrence?

The correct answer is a functional assessment, which is specifically designed to identify the underlying reasons or functions behind a behavior. This type of assessment involves observing the behavior in real-time contexts to determine the antecedents (triggers) and consequences that maintain the behavior. By understanding how a behavior operates in its environment and what reinforces it, practitioners can develop effective interventions to address it.

In contrast, formative assessments are primarily used to monitor student learning and guide teaching, focusing on ongoing monitoring rather than behavior functions. Diagnostic assessments are aimed at identifying specific learning needs or areas of strength and weakness, usually in a more structured and less observational manner. Summative assessments evaluate student learning at the end of an instructional period, measuring what has been learned rather than understanding the dynamics of behavior occurrence. Therefore, functional assessments uniquely provide insight into the relationship between behavior and environmental factors, allowing for targeted intervention.