Measurement validity in cross-cultural comparative research

BACKGROUND: The purpose of this article is to review the procedures to establish measurement validity in cross-cultural comparative research, including recent developments in the quantitative assessment of cross-cultural construct validity. METHODS: A narrative review, illustrated by selected examples, of methods in four areas--formative conceptual research, translation and adaptation, criterion validity and construct validity. RESULTS: Valid assessment across cultures requires qualitative research to investigate the cultural relevance of the construct, a careful translation and adaptation of a common measure, followed by pre-testing and cognitive interviews on the populations to be tested. Full criterion validation across diverse cultures may be a chimera given the difficulty in establishing a universally applicable 'gold standard'. Quantitative analyses can, however, have a part to play in establishing construct validity across cultures. Scale internal consistency, inter-item and item-total correlations and test-retest reliability provide basic support for the viability of a measure in a new cultural setting. Exploratory factor analysis can be used to compare factors and factor loadings. The hypothesis of 'measurement invariance' across countries and cultures can be tested explicitly using confirmatory factor analysis (common underlying factors and factor loadings) and Rasch models (common hierarchality of items). Despite measurement invariance, threshold effects arising from cultural differences in norms, or expectations, or expressions of mental distress may still be a problem. CONCLUSIONS: There are few examples in the cross-cultural mental health literature of demonstrably valid culture-fair comparison. Much more, could, in principle, be done either to demonstrate measurement invariance, or to identify and explore sources of heterogeneity.