Single-sample reliability evidence cannot establish a scale’s trustworthiness

Evidence

However, reliability derived from just one sample and with only one method of measuring reliability is incomplete. Replication of these internal consistency findings using a different sample is imperative to verify the accuracy of such findings. Moreover, other tests of reliability, such as test–retest reliability, are necessary to provide additional support for an instrument’s reliability (DeVellis, 1991). — Sherman A. Lee, Chelsea A. Reid, Stephen D. Short, Jeffrey A. Gibbons, Ruth Yeh, and Matthew L. Campbell, Fear of Muslims, 22

Categorization

• QUESTION: Has the Islamophobia Scale’s internal consistency been replicated in an independent sample, and does it hold up on test-retest?
• XREF: Generic instrument-validation logic (DeVellis) reusable for judging any psychometric measure you cite. — connects to: Combining exploratory and confirmatory factor analysis produces theory-driven results robust across samples — Ruiqian Li and Paul Froese, The Duality of American Christian…, 94