Kuder-Richardson Formula 20 is used to estimate what?

• A. Internal Consistency
• B. Test-Retest Reliability
• C. Face Validity
• D. Construct Validity

Answer: (A)

Kuder-Richardson Formula 20 assesses internal consistency reliability for tests with dichotomous (right/wrong) items. It tells you how well the test items hang together, or consistently relate to the same underlying construct. A higher KR-20 indicates greater homogeneity among items, meaning the items collectively reflect the same attribute rather than random variation. It doesn’t measure stability over time (that’s test-retest reliability), nor does it address whether the test looks like it measures what it should (face validity) or whether it truly captures the theoretical construct (construct validity). For binary-scored items, KR-20 is the appropriate internal-consistency estimate; for more complex item formats, Cronbach’s alpha is used as a general alternative.