The Water Insecurity Experiences (WISE) Scales are suitable for use in high-income settings: findings from cognitive interviews and nationally representative surveys

Background: The Water Insecurity Experiences Scales are validated tools for reliably and comparably assessing experiences with water access and use in low- and middle-income countries. Although theoretically applicable in high-income countries, their performance in these settings has not been assessed. This study therefore examined whether the Water Insecurity Experiences Scales function similarly in high-income countries, and if they generated measures comparable to those in low- and middle-income countries. Methods: We conducted cognitive interviews with 73 adults from four high-income countries (Bulgaria, the Netherlands, the United Kingdom, and the United States) to assess whether participants understood the items in the Individual Water Insecurity Experiences Scale as intended. We then used nationally representative Gallup World Poll data from two high-income countries (Australia, the United States) and three low- and middle-income countries (Bangladesh, Brazil, and Uganda) to evaluate internal consistency, unidimensionality, and measurement invariance (n = 4,928). Construct validity was assessed by testing hypothesized associations between water insecurity scores and wealth, household size, self-reported stress, and satisfaction with water quality within Australia and the United States. Results: Items were understood as intended by participants in cognitive interviews. The prevalence of moderate-to-high water insecurity was low in Australia (3.7%) and the United States (1.0%). In both countries, the scale was internally consistent, conformed to the unidimensional structure, and demonstrated good model fit based on criteria established a priori. Configural and scalar measurement invariance were supported across the examined low-, middle-, and high-income countries. Regarding scale validity, water insecurity scores were associated with sociodemographic characteristics (wealth, household size), self-reported stress, and satisfaction with water quality in the directions hypothesized. For example, the percentage of participants with moderate-to-high water insecurity reporting stress during the previous day or water quality dissatisfaction was 1.80 times (95% CI: 1.50, 2.17) and 4.12 times (95% CI: 2.87, 5.93) higher, respectively, than among those with no-to-low water insecurity. Conclusions: The Individual Water Insecurity Experiences Scale performs well in high-income countries and yields cross-country comparable measures, supporting its use for global monitoring of water insecurity.