Formative assessment helps to answer these questions:
Formative assessment assesses student learning while it is taking place. It provides detailed feedback on the strengths and weaknesses of teaching and learning strategies so faculty can make immediate modifications to classroom activities and assignments. (Adapted from Assessing Student Learning by Linda Suskie, 2004).
The goal of formative assessment is to informally allow students to demonstrate their level of understanding of a specific topic, which in turn helps the instructor recognize what teaching techniques are most effective.