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 may be used to assist teachers in making summative judgements 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 appropriate programs for students.
Teachers conduct all three types of evaluation during the course of the school year.
The evaluation process involves the teacher as a decision maker throughout all four phases. The teacher's decisions in this phase form the basis for the remaining phases. During the assessment phase , the teacher identifies information-gathering strategies, constructs or selects instruments, administers them to the student, and collects the information on student learning progress. The teacher continues to make decisions in this phase. During the evaluation phase , the teacher interprets the assessment information and makes judgements about student progress.