Kendall's W measures agreement among raters.

• A. Spearman's rho
• B. Intraclass correlation
• C. Cronbach's alpha
• D. Kendall's W

Answer: (D)

Kendall's W is the statistic designed to measure how much agreement there is among multiple raters who rank a set of items. It looks at how consistently the raters order the items. If every rater assigns the same ranking, W equals 1, indicating perfect agreement. If the raters disagree a lot and their rankings are essentially random relative to each other, W moves toward 0, indicating little or no agreement beyond chance. This makes Kendall's W especially suitable for ordinal data with more than two raters.

The other options address different concepts. Spearman's rho measures the association between two sets of ranks, not agreement among several raters. Intraclass correlation assesses reliability of quantitative measurements from multiple raters but is tailored to continuous data. Cronbach's alpha evaluates internal consistency of a set of items on a test, not how raters agree in ranking.