Measurement structure, invariance, and item functioning of intimate partner violence scales in high-income countries: Results from 30 population-based surveys.

Objective: Intimate partner violence (IPV) is a serious and prevalent threat to the health of women worldwide, yet limitations in measurement hinder efforts to monitor, prevent, and respond to this global challenge. These include variability in definitions and assessment tools, small item sets, lack of comparability across countries, and variability in outcome construction in IPV studies. Methods: We performed exploratory and confirmatory factor analysis, measurement invariance testing, and item response theory analysis on IPV data from publicly available, population-based surveys conducted in 28 EU countries and two US states. Results: We found that a unidimensional model of IPV based on 30 dichotomous indicators in the EU and 22 dichotomous indicators in the US described IPV well in all countries and states and was strictly invariant across countries and states. Additionally, we identified items that might be removed from the two scales without substantive information loss and high-information items that might be added to IPV scales used in other countries to improve content validity. Finally, we found that outcome construction (dichotomized/count of acts/factor scores) impacted the magnitude, but not the significance, of associations between IPV experience and general health measures. Conclusions: Our findings highlight opportunities to improve commonly used IPV scales and suggest that psychological IPV and controlling behaviors are salient aspects of women's IPV experience that should be incorporated into national and international reporting mechanisms.