method notes

method note

Scale adaptation: translation is not enough

How do you adapt a scale developed in another language?

Adaptation requires at least three stages: linguistic equivalence through forward–back translation and expert review, comprehensibility through piloting, and re-demonstration of construct validity in the new sample. You cannot assume the original factor structure will reappear, and cross-cultural comparison is not permitted until measurement invariance has been tested.

Measurement invariance

Comparing two groups' means assumes the scale measures the same thing in both. That assumption is testable: configural invariance (same structure), metric invariance (same loadings), scalar invariance (same intercepts). Mean comparison requires at least the scalar level, and most cross-cultural studies skip the step.

The common adaptation error

Citing the reliability and validity figures from the scale's original paper does not substitute for adaptation. That evidence has to be reproduced in every new sample.

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Written for researchers and graduate students. Conventions described here are conventions, not rules — check them against your own design before you report.