Is the extent to which a test yields a consistent, reproducible measure of performance.

Reliability

Explanation:

In research, the term reliability refers to the degree to which research and experiments produce stable and consistent results. Since the results are consistent, we can expect that one person can go through the test more than one time and he/she will get similar results every time, thus, you would expect the results to be the same.

Therefore, we can say that reliability is the extent to which a test yields a consistent, reproducible measure of performance.