Correct Answer:
B. Longer test
Reliability refers to the consistency and stability of a test's results. A reliable test yields similar scores when administered repeatedly under similar conditions or when different forms of the test are used. Several factors influence test reliability.
- The reliability of a test generally increases with a longer test (B). More items provide a larger sample of the knowledge or skill being measured, which helps to average out random errors or lucky guesses on individual items. This leads to more consistent and stable scores, making the overall measurement more dependable.
- A short length (A) test is more susceptible to random error and less likely to provide a consistent measure.
- Ambiguous items (C) introduce confusion and inconsistency, thereby decreasing reliability.
- Subjectivity (D) in scoring, especially without clear rubrics, introduces variability and inconsistency, which also decreases reliability.
Hence, increasing the number of relevant and well-constructed items enhances a test's reliability.