What does the standard error of measurement indicate?

The standard error of measurement is a statistical concept that essentially reflects the reliability of a test score. It indicates how much a student's observed test score may vary due to measurement error. This variation means that if a student were to take the same test multiple times under the same conditions, the scores could differ due to this measurement error.

Option C correctly captures this definition, as it refers to the standard deviation of test scores from repeated test-takers. This implies that when multiple students take a test, the standard error of measurement helps quantify how much their scores may fluctuate around the true score—essentially illustrating the variability or precision of the test in measuring what it is intended to measure.

The other choices do not align closely with the concept of the standard error of measurement. For instance, while the average grade a student will achieve is related to performance, it does not provide any information about the reliability or variation of that grade. Similarly, while assessing the consistency of a test score over repeated trials might touch on reliability, it is not specific enough to denote the variability aspect that the standard error expresses. Lastly, the correlation between different test forms speaks to the relationships between tests rather than individual score variability, which is what the standard error of measurement is primarily focused on