Assessment is a preliminary phase. In this phase, various techniques are used to gather information about student progress. Formative evaluation is an ongoing classroom process that keeps students and educators informed of students' progress. The main purpose of formative evaluation is to improve instruction. Students are provided direction for future learning and are encouraged to take responsibility for their own progress.
Summative evaluation occurs most often at the end of the unit of study.
Its primary purpose is to determine what has been learned over a period of time, to summarize student progress, and to report on progress to students, parents, and educators. Seldom are evaluations strictly formative or summative. Diagnostic evaluation usually occurs at the beginning of the school year or before a unit of instruction.