Assessment of medical knowledge: the pros and cons of using true/false multiple choice questions.

True/false multiple choice items, commonly referred to as true/ false multiple choice questions (MCQs), were previously a widely used selected response examination format. They can be written relatively easily and cover a wide range of content. Educational researchers have however highlighted several adverse features of this format that make it inappropriate for many assessment settings. These include: (i) there is a high chance of guessing the correct answer; (ii) some marks are not awarded for knowing the correct answer, but for knowing that an answer is incorrect; (iii) they are weak in discriminating between high and low performers; (iv) identifying items which are absolutely true or false may lead to assessment of trivial knowledge; (v) there are difficulties with constructing flawless items; (vi) they may not encourage learning around the items; and (vii) they may not assess what they purport to assess. Many assessment agencies abandoned the use of this format decades ago due to these shortcomings. The use of single best answer (SBA) and extended matching item (EMI) formats helps overcome or minimize the above weaknesses. Assessors who plan to change to SBA or EMI formats from true/false MCQs may, however, need to increase the number of questions to include a representative sample of the curriculum (lengthening the question paper). However, they may not need to increase the examination time, as in general students can answer more SBAs or EMIs than true/false MCQs per unit time. It is time that we reflect upon the disadvantages of true/false MCQs and review their place in our assessment toolkit, as their use in summative examinations may not be fair to students, especially 'good' students.