Which type of reliability measures the variability in repeated measures for the same individual?

Absolute reliability is focused on the consistency of repeated measurements for the same individual, assessing the variability in those measures. This type of reliability essentially quantifies how much repeated trials can differ while still reflecting the true performance of the individual being tested.

In the context of performance testing, understanding absolute reliability is crucial because it helps to determine how stable the measurements are across multiple trials. For example, if an athlete's sprint time is measured multiple times, absolute reliability would evaluate how consistent these times are, regardless of the absolute values of speed or performance.

The other types of reliability mentioned serve different functions. Relative reliability assesses the consistency of scores between individuals, indicating how well relative differences between people are maintained across repeated measures. Re-test reliability involves measuring the same individuals at different times and seeing if results are consistent over time, but it does not focus specifically on variability for the same individual in repeated trials. Intra-rater reliability refers to the consistency of measurements taken by the same person across multiple trials, but it is not specifically about the variability of those measures for the same individual.

Thus, absolute reliability is the best answer when examining variability in repeated measures for the same individual.