If standardized test data are used in the principal's study, which should the principal consider to measure performance across repeated test administrations?

If standardized test data are used in the principal's study, which should the principal consider to measure performance across repeated test administrations?

(a) Reliability
(b) Validity
(c) Generalizability
(d) Reproducibility
✅ Correct option: (a) Reliability
Explanation: Reliability measures consistency of test results over repeated administrations.