Which reliability concept concerns the stability of test scores over time?

Which reliability concept concerns the stability of test scores over time?

• A. External reliability
• B. Internal reliability
• C. Cronbach's alpha
• D. Factor analysis

Answer: (A)

The idea being tested is the stability of scores across time, which is captured by external reliability through test-retest reliability. When the same measure is given to the same people on two different occasions, a high correlation between the two sets of scores indicates that the test yields stable results over time and is not overly influenced by random fluctuations or momentary states. This stability is what external reliability is assessing. Internal reliability, by contrast, looks at how consistently the items on the test measure the same construct at one point in time, typically quantified with Cronbach's alpha. Factor analysis isn’t a reliability metric; it’s used to explore the underlying structure or dimensions of a test, not its score stability over time.

The idea being tested is the stability of scores across time, which is captured by external reliability through test-retest reliability. When the same measure is given to the same people on two different occasions, a high correlation between the two sets of scores indicates that the test yields stable results over time and is not overly influenced by random fluctuations or momentary states. This stability is what external reliability is assessing.

Internal reliability, by contrast, looks at how consistently the items on the test measure the same construct at one point in time, typically quantified with Cronbach's alpha. Factor analysis isn’t a reliability metric; it’s used to explore the underlying structure or dimensions of a test, not its score stability over time.