What is Cronbach's alpha and what does it indicate?

• A. A measure of test speed.
• B. A statistic that measures internal consistency reliability of a test; higher values indicate better consistency.
• C. A method to calculate grade point average.
• D. A criterion for standard-setting.

Answer: (B)

Cronbach's alpha is a statistic used to assess internal consistency reliability of a test, which means how well the items on a scale work together to measure the same underlying construct. When the items are closely related, responses tend to move together, and Cronbach's alpha rises. A higher alpha suggests greater consistency among item responses, indicating the scale is reliably measuring what it intends to measure. Keep in mind that alpha is influenced by the number of items and by how closely related they are; very high values can indicate redundancy, while very low values suggest the items may not be tapping the same construct. It does not tell you about speed, GPA calculation, or standard-setting, and it is not a direct measure of validity.