Reliability¶
Estimates the internal consistency of a multi-item scale.
When to use it¶
After designing or administering a questionnaire scale, to check that its items hang together — and to see whether dropping an item would help.
Inputs¶
Items — two or more numeric (or ordinal) columns that make up one scale. Reverse-keyed items should be corrected first with Invert Scale (see Invert Scale).
Options¶
Coefficient type — the inter-item correlation used (e.g. Pearson).
McDonald’s omega — reports ω in addition to Cronbach’s α.
Scale name — a label for the output.
Verbal report — dropdown for how much plain-language interpretation to add (None / Key findings / Significant only / Full).
Verbal indicators and Number columns.
Output¶
Cronbach’s α (and McDonald’s ω if requested) with an interpretation.
An item statistics table including item–total correlations and α if the item is removed (plus ω if removed when McDonald’s omega is enabled), which flags items that weaken the scale. With Verbal indicators on, each coefficient gets a plain-language reading, and the item table shows a separate “Improves α?” / “Improves ω?” verdict per coefficient.
Notes¶
At least two items are required.
A high “alpha if removed” relative to the overall alpha suggests an item may not belong on the scale.