What type of test is designed to assess what students have learned in a specific subject area?

An achievement test is specifically designed to evaluate what students have learned in a particular subject area. These tests measure knowledge and skills acquired through instruction and coursework, providing insight into a student's academic performance and mastery of concepts. For example, a mathematics achievement test might assess a student's understanding of algebra or geometry after completing relevant coursework.

In contrast, aptitude tests measure a student's potential to learn or perform in certain areas, rather than what they have already learned. Personality tests assess individual characteristics and traits, which are unrelated to academic achievement. Diagnostic tests are used to identify specific learning difficulties or areas where a student may need additional support, rather than focusing solely on the accumulation of knowledge in a subject. Therefore, the most fitting choice for assessing what students have learned is the achievement test.