McDonald's ω estimates model-based reliability from a single-factor model — the modern replacement for Cronbach's α when tau-equivalence is doubtful.
α assumes every item measures the construct equally well (tau-equivalence); when loadings differ, α underestimates reliability. ω computes reliability from a factor model's loadings and uniquenesses, so unequal loadings are handled correctly.
Computed from a single-factor model; reported alongside α and each item's general-factor loading.
≥ 3 numeric item columns.
ω total, ω hierarchical, Cronbach's α (reference), general-factor loading per item.
ω ≥ 0.8 commonly read as good reliability. A low-loading item suggests it measures something else — consider dropping it.