What does reliability in testing refer to?

Reliability in testing specifically refers to the consistency of a test's results when it is administered multiple times to the same individual or group, under similar conditions. This means that if a test is reliable, it should yield the same or very similar scores upon repeated testing, assuming that the underlying trait being measured has not changed.

For example, if a student takes a math proficiency test today and again in a week, a reliable test would produce comparable scores if their math skills have remained stable. This aspect is crucial in evaluating the trustworthiness of a test, as high reliability indicates that the test measures what it is supposed to measure consistently over time.

Other options touch on different principles of assessment quality but do not define reliability directly. Providing accurate results under various conditions pertains more to validity and ensures that a test measures what it claims to measure across different scenarios. Assessing a wide range of skills relates to comprehensiveness but does not guarantee consistency in measurement. Similarly, the ability to be administered in different languages might address usability or accessibility rather than the test's reliability in producing consistent scores.