A performance assessment requires you to perform a task rather than select an answer from a ready-made list. In this method of assessment, you are actively involved in demonstrating what you have learned. Performance assessments may be more valid indicators of your knowledge and abilities than written tests.
Portfolios are also a form of performance assessment. According to the "Field-tested Learning Assessment Guide" (http://www.flaguide.org/cat/portfolios/portfolios1.php), student portfolios are a collection of evidence, prepared by the student and evaluated by the faculty member, to demonstrate mastery, comprehension, application, and synthesis of a given set of concepts. To create a high quality portfolio, students must organize, synthesize, and clearly describe their achievements and effectively communicate what they have learned.
Case-based assessment instruments evaluate the extent to which you are able to handle authentic, real-world problems. Case-based learning focuses on building knowledge within a group that is working together to examine the facts presented in the case. Much of case-based learning involves learners striving to resolve questions that have no single right answer. Emphasis is placed on the process of resolving a stated problem rather than on the actual answers to the questions.