Formative evaluation is an ongoing classroom process that keeps students and educators informed of students' progress towards program learning objectives. The main purpose of formative evaluation is to improve instruction and student learning. It provides teachers with valuable information for instructional modifications. This type of evaluation helps teachers understand the degree to which students are learning the course material and the extent to which their knowledge, understandings, skills, and attitudes are developing. Students are provided direction for future learning and are encouraged to take responsibility for their own progress.
Summative evaluation is designed to be used at the end of instruction.
Seldom are evaluations strictly formative or strictly summative. 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 decisions 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 beginning of the school year or before a unit of instruction.