High reliability implies what about measurement error?

• A. A high reliability means the test has minimal measurement error.
• B. Reliability eliminates all errors.
• C. Reliability is the same as validity, so errors don’t matter.
• D. Reliability only concerns score interpretation.

Answer: (A)

High reliability means the scores are consistent reflections of the true attribute rather than random fluctuations. Since observed score equals true score plus measurement error, when reliability is high, most of the variability in scores comes from the true differences, not error. That shows measurement error is minimal. It’s important to note that errors aren’t completely eliminated, and reliability isn’t the same as validity (a test can be reliable but not valid). Reliability is about consistency across items or administrations, not just how scores are interpreted.