Which statement correctly defines the true score in assessment measurement?

• A. The true score is an estimate of the actual score if the student had a zero-error score.
• B. The true score is the student's observed score on that assessment.
• C. The true score is the average of the student's scores across all assessments.
• D. The true score is the sum of the student's errors across assessments.

Answer: (A)

In assessment measurement, the true score is the score a student would obtain if there were no measurement errors. Every observed score includes some error due to momentary factors, item characteristics, and administration conditions, so the true score represents that ideal, error-free level of performance. Since we can’t observe this flawless score directly, we describe it as an estimate of what the student would actually earn under perfect conditions. That’s why the statement saying the true score is an estimate of the actual score if the student had a zero-error score best captures the idea.

The observed score isn’t the true score because it contains error; taking averages across assessments mixes different performances, not the single, ideal score; and summing errors across assessments describes the measurement error itself, not the underlying true score.