The Sexual Experiences Survey: interpretation and validity.

The Sexual Experiences Survey (Koss, Gidycz, & Wisniewski, 1987) is a commonly used instrument for assessing various degrees of sexual aggression and victimization among male offenders and female victims. Rasch analysis was used to transform qualitative raw score observations into objective linear measures using the responses of a national sample of 6,159 higher education men and women across the United States, aged 18-24. This paper supports the construct validity of the survey through evaluation of the item hierarchy, fit statistics, and separation indices. Findings confirm a "dimensional" perspective on rape, suggesting that sexually aggressive behaviors can be scaled along a single continuum from normal to extreme sexual behavior. The item hierarchy reveals an arrangement of sexually aggressive acts in an order of mild to severe, which compares with the one theorized by the authors of the SES. Identity plots demonstrate the validity of using a common set of SES item calibrations to measure both male and female respondents. For interpretation of person responses to the SES, three conclusions are suggested. First, Rasch analysis must be employed to examine item responses effectively. Second, when the survey is administered to a college sample aged 18-24, the item calibrations obtained in this paper can be used to measure offenders and victims. Third, a total raw score-to-measure conversion is not always sufficient to interpret person measures. Instead, a scalogram method needs be added to the Rasch analysis to separate the measures of offenders and victims who complete the survey. Implications for future research are discussed.