Performance assessment measures students skills based on authentic tasks such as activities, exercises, or problems that require students to show what they can do.
In some cases performance tasks are used to have students demonstrate their understanding of a concept or topic by applying their knowledge to a particular situation. For example, students might be given a current political map of Africa showing the names and locations of countries and a similar map from 1945 and be asked to identify and explain differences and similarities. To be more authentic (more like what someone might be expected to do in the adult world), the task might be to prepare a newspaper article explaining the changes.
Because performance assessments require students to actively demonstrate what they know, they can be a more valid indicator of students' knowledge and abilities than other assessment methods.