A multiple choice exam can test knowledge at several levels.
Low level: recall data, report observations, identify, define.
Convergent questions: find similarities and differences, identify relationships, draw inferences, explain.
Divergent questions: develop a theory, make predictions, develop a generalization, speculate.
Length: You should not give the students less than one minute per question (a maximum of 50 questions for a 50 minute class period). You may choose to give even fewer questions depending on the number of responses per question or calculations required
.Difficulty: In order to discriminate between the students who know the material covered on the exam and those that do not know the material, true/false items should have a difficulty of about 75% (i.e., 75% of the class should get the answer correct). Four response multiple choice items should have a difficulty of about 63%. Items with difficulty of greater then 90% or less than 30% should be revised. An exception to the 90% difficulty can be made at the beginning of an exam. To put students at ease, the first few items can be easy (have a difficulty of 90% or more). Difficulty can be measured by any ScanTron grading machine. Use the Item Analysis form for the stand alone grading, or get the full print out from the TRC computer-based scoring.
Format: Presenting items on overheads or slides may be necessary for some visual information, but should generally be avoided. This is might separate 'good' test takers from 'poor' test takers but will not necessarily measure understanding of the target material. Allowing students to move through the items at their own pace and giving them space on the page to make comments will help your test assess understanding of the target material.
See tips for item construction, / cheating prevention, / item examples