There are a plethora of different assessments used in education, but the three most commonly used ones are diagnostic/pre-, formative, and summative assessments:
Diagnostic assessments/Pre-assessments are conducted before teaching a new subject or at the start of an academic year, to help educators understand students' existing knowledge. This preliminary evaluation can reveal students' understanding of prerequisite topics, and their preferred learning styles (e.g., visual, auditory, textual). The focus of these assessments is not on complete knowledge of the subject, but on grasping existing understanding levels.
Formative assessments are conducted during a course to evaluate ongoing learning effectiveness. These mid-term tests aim to identify areas of struggle for students and areas that require more attention to meet curriculum requirements. Primarily low-stakes, the goal of formative assessments is to provide insight for further learning refinement rather than grading.
Summative assessments, often high-stakes, are used to evaluate student learning at the end of a course or term. These assessments measure student understanding of the taught subject and assign a final grade. Unlike formative assessments, summative assessments carry significant implications for the student.