Descriptive assessments are there to helps identify the causes and effects of behavior. If you're looking at a child, you'd observe and record them in their natural environment. You'd be looking to note the antecedent to the behavior (child's classmate taking their pencil), the child's behavior (hitting their classmate to get the pencil back), and the consequences (child being sent out of the room). So, yes, descriptive assessments CAN identify cause-effect relations (however, they are not always accurate).
