For example, summative evaluation can be used formatively to assist teachers in making decisions about changes to instructional strategies or other aspects of students' learning programs. Similarly, formative evaluation can be used to assist teachers in making summative judgments about student progress. However, it is important that teachers make clear to students the purpose of assessments and whether they will later be used summatively. Diagnostic evaluation usually occurs at the beginning of the school year or before a unit of instruction. Diagnostic evaluation provides information essential to teachers in designing an appropriate program for students.
Teachers conduct all three types of evaluation during the course of the school year.