Evaluating and Refining the Construct of Sexual Quality With Item Response Theory: Development of the Quality of Sex Inventory

摘要

This study took a critical look at the construct of sexual quality. The 65 items of four well-validated self-report measures of sexual satisfaction (the Index of Sexual Satisfaction [ISS], Hudson, Harrison, & Crosscup, 1981; the Global Measure of Sexual Satisfaction [GMSEX], Lawrance & Byers, 1995; the Pinney Sexual Satisfaction Inventory [PSSI], Pinney, Gerrard, & Denney, 1987; the Young Sexual Satisfaction Scale [YSSS], Young, Denny, Luquis, & Young, 1998) and an additional 74 potential sexual quality items were given to 3060 online participants. Using Item Response Theory (IRT), we demonstrated that the ISS, YSSS, and PSSI scales provided suboptimal levels of precision in assessing sexual quality, particularly given the length of those scales. Exploratory factor analyses, IRT, differential item functioning analyses, and longitudinal responsiveness analyses were used to develop and evaluate the Quality of Sex Inventory. Results suggested that, in comparison to existing scales, the QSI (1) offers investigators and clinicians more theoretically focused scales, (2) distinguishes sexual satisfaction from sexual dissatisfaction, and (3) offers greater precision and power for detecting differences with (4) comparably high levels of responsiveness for detecting change over time despite being notably shorter than most of the existing scales. The QSI-satisfaction subscales demonstrated strong convergent validity with other measures of sexual satisfaction and excellent construct validity with anchor scales from the nomological net surrounding that construct, suggesting that they continue to assess the same theoretical construct as prior scales. Implications for research are discussed.