Impact of Measurement Variability on Study Inference in Partner Violence Prevention Trials in Low- and Middle-Income Countries

Abstract

In lower- and middle-income countries (LMICs), studies of interventions to reduce intimate partner violence (IPV) are expanding, yet measurement equivalence of the IPV construct—the primary outcome in these investigations—has not been established. We assessed the measurement equivalence of physical and sexual IPV item sets used in recent trials in LMICs and tested the impact of noninvariance on study inference. With data from four intervention trials ( N = 3,545) completed before 2020, we used multiple-group confirmatory factor analysis to assess invariance across arms, over time, and across studies. We also calculated average treatment effects adjusting for covariate imbalance to assess concordance with published results. Most items functioned equivalently within studies at baseline and end line. Some evidence of longitudinal noninvariance was observed in at least one study arm in three studies, but did not meaningfully affect latent means or effect-size estimates. Evidence of partial invariance across studies at baseline and strict invariance over time was observed. Common measures of physical and sexual IPV were valid for measuring intervention impact in these samples. The study highlights the need for harmonized use of the tested scale, content validity assessments, and routine measurement equivalence testing to ensure valid inferences about intervention effectiveness.