Objective test items may be free-response, where the answer is supplied by the examinee, or fixed-response, where the examinee selects the response from those supplied by the examiner. In this chapter discussion will be confined to fixed-response items, although much of what is written also applies with equal force to free-response items. Examining boards who can afford to employ teams of experienced item writers usually have five responses, but for school use four is adequate. An examination of the literature on objective testing, particularly the American literature, will reveal a large number of different types. The criteria for certain subjects in the General Certificate of Secondary Education, for example science, specify that multiple choice items are to be preferred, the more complex types such as multiple completion and assertion-reason, should be used with caution. Because of the nature of objective tests it is essential that ambiguities, errors and omissions are corrected before the test is used operationally.