The true/false (T/F) format is limited in usefulness compared with most other formats but is still common. A few reasons for its refusal to fade into oblivion are the relative ease of writing a true/false item and the ease and objectivity of scoring it. There are more problems than benefits, however:
1. T/F items tend to focus on trivial facts, rather than significant concepts. As a result, they tend to be either too easy or unreasonably difficult.
2. T/F items are much more likely to be ambiguous or “tricky” to answer. Often the answer turns on a single word. A student may need to analyze multiple words in the item to catch the one that is incorrect.
3. T/F items are too rewarding for guessers, since a random answer has a 50% chance of being correct. On a curriculum-based test, where a passing score typically is 75% - 80%, a chance of 50% may not be enough to boost the overall test grade. On a norm-referenced achievement test, guessing with a chance of 50% may significantly affect the overall score.
Suggestions for True/False Items
1. Avoid vague, indefinite, or broad terms in favor of precise statements. Good test items must be unambiguous, and T/F items even more so.
2. If the correctness of a statement hinges on a particular word or phrase, highlight or emphasize that word or phrase.
3. Avoid negative statements if at all possible. Negative statements are harder to decode, particularly those with two negatives.
4. Include similar numbers of true and false items and make them similar in length.
5. Group T/F items under a common statement, story, illustration, graph, or other material. This reduces the amount of ambiguity possible, since the items come from a specific frame of reference.
6. Avoid generalizations such as all, always, never, or none, since they usually trigger a false statement. Also avoid qualifiers like sometimes, generally, often, and can be, since they are often indicators of a true statement.