Development and Validation of the Power Imbalance in Couples Scale.

Few researchers have quantitatively explored the relationship power-HIV risk nexus in same-sex male couples. We developed and validated the Power Imbalance in Couples Scale (PICS) to measure relationship power among men in same-sex, committed relationships and its association with sexual risk behaviors. We recruited three independent and diverse samples of male couples in the greater San Francisco and New York City metropolitan areas and conducted qualitative interviews (N1 = 96) to inform item development, followed by two quantitative surveys (N2 = 341; N3 = 434) to assess the construct, predictive, convergent, and discriminant validity of the PICS. Exploratory factor analysis of the first survey's data yielded four factors-overtly controlling partner, supportive partner, conflict avoidant actor, and overtly controlling actor-that accounted for more than 50% of the shared variance among the PICS items. Confirmatory factor analysis (CFA) of the second survey's data supported these four factors: χ2(1823) = 2493.40, p < .001; CFI = .96, RMSEA = .03 and WRMR = 1.33. Strong interfactor correlations suggested the presence of a higher-order general perception of power imbalance factor; a higher-order factor CFA model was comparable in fit to the correlated lower-order factors' CFA: χ2(2) = 2.00, p = .37. Internal reliability of the PICS scale was strong: α = .94. Men perceiving greater power imbalances in their relationships had higher odds of engaging in condomless anal intercourse with outside partners of discordant or unknown HIV status (OR 1.27; 95% CI 1.01-1.60; p = .04). The PICS is an important contribution to measuring relationship power imbalance and its sequelae among male couples; it is applicable to research on relationships, sexuality, couples, and HIV prevention.