It provides teachers with valuable information upon which instructional decisions and modifications can be made and provides students with direction for future learning. Teachers engage in formative evaluation frequently during daily classroom activities. For example, formative evaluations are made during writing conferences, small group activities or whole-class discussions. In these situations, the teacher observes, listens and judges the response or contribution from the students. As a result, a teacher might decide that the class, a group of students or an individual student needs instruction on a specific skill or concept.
Summative evaluation occurs most often at the end of a unit of study.
The primary purposes are to determine what knowledge, skills, abilities and attitudes have developed over a period of time, to summarize student progress, and to report progress relative to the curriculum objectives to students, parents or care givers, and teachers. Seldom are evaluations strictly formative or summative. For example, summative evaluation can be used formatively to assist teachers in making decisions about changes to instructional methods, curriculum content or the learning environment. Similarly, formative evaluation assists teachers in making summative judgements about student progress. Diagnostic evaluation usually occurs at the beginning of the school year or before a unit of instruction.