McDonald's Omega (ω)
HR & WorkReliability: statistical estimator3 sample items
About this scale
A composite-reliability estimator preferred over Cronbach's alpha when item loadings vary. Omega = (sum loadings)² / [(sum loadings)² + sum residual variances]. Range 0–1.
Sample item(s)
“Estimate factor loadings via CFA”
“Compute omega = (sum loadings)² / [(sum loadings)² + sum residual variances]”
“Interpret like alpha (≥0.70 acceptable)”
Reliability
Reported internal consistency: statistical estimator. As a rule of thumb, Cronbach’s α ≥ .70 is considered acceptable, ≥ .80 good, and ≥ .90 excellent for established measures.
Notes
Modern alternative to Cronbach alpha.
Source & citation
McDonald, R. P. (1999): Test theory: A unified treatment. Lawrence Erlbaum.
McDonald, R. P. (1999): Test theory: A unified treatment. Lawrence Erlbaum.
Source. Scale details are summarised from the publication cited above. Always consult the original source for the full item set, scoring, and permission to use.
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