Abstract
<title>Abstract</title> <p>Background Water insecurity is a common challenge in resource-constrained settings that particularly impacts women. Locally adapted and validated water insecurity measures provide a more robust basis for intervention. Our aim was to culturally adapt and psychometrically validate the HWISE scale for Sidaamu Afoo speakers using ordinal response categories rather than truly continuous measurements. Methods We explored factors using Horn's Parallel Analysis on a polychoric correlation matrix, which accounts for ordinal response categories. Data suitability was confirmed by Kaiser-Meyer-Olkin and Bartlett's sphericity indices. We validated psychometric properties using data from 264 randomly selected adult Sidaamu Afoo-speaking women in Ethiopia. Reliability was assessed via classical test theory, using the ordinal coefficient α for internal consistency and the intraclass correlation coefficient (ICC) for temporal stability. Statistical analyses were performed using R. Results The Kaiser-Meyer-Olkin value of 0.942 confirmed the sampling adequacy of each item and the HWISE scale. A significant Bartlett’s test (p < 0.05) indicated that the correlation matrix was suitable for factorization. The adapted HWISE scale presented a unidimensional structure, driving 67.6% of total variance. The items demonstrated internal consistency (α = 0.96) and stability across repeated measures (ICC = 0.93). The scale further showed convergent validity, confirmed by a significant correlation with external constructs, and discriminant validity, distinguished by known-group differentiation. Conclusion The adapted HWISE scale proved valid and reliable in measuring retrospective water insecurity experiences among Sidaamu Afoo-speaking adult women in Ethiopia. Future studies should diversify their sample and address seasonal variations.</p>