The Sociosexual Orientation Inventory SOI-R is a 9-item self-report questionnaire designed to measure individuals differences in the tendency to have casual, uncommitted sexual relationships. This tendency, termed sociosexual orientation is divided into three facets measured by the inventory: Sociosexuality as a concept was introduced by Alfred Kinsey   "Sociosexual orientation index" describe differences in individuals tendency to engage in uncommitted sexual relationships.
Minimal research was done until interest in the topic markedly increased when Gangestad and Simpson released their 5-item Sociosexual Orientation Inventory in There currently exist two variations on the SOI-R currently available in 25 languages, a 9-point response scale for integration with the original Gangestad and Simpson SOI and a 5-point response scale for the majority of subjects.
The language versions include Czech,  English,  Hungarian,  or Polish.
Significant sex differences have been found between men and women on the scale, with a significantly larger correlation between the attitude and behavior of the SOI-R in women compared to men proposed to be due to lower opportunity for behavior. Improving on the previous Gangestad and Simpson Sociosexuality scale, the three factors appeared to make unique contributions and have discriminant validity.
Desire made Sociosexual orientation index contributions to the prediction of past sexual and relationship behaviors, observer-rated attractiveness, self-perceived mate value, and male and female flirting behavior, as well as having links with sex drive and relationship quality.
Attitude appears responsible for the effect of sociosexuality on mate preferences, assortative mating, and romantic partner's flirtatiousness outside the relationship. From Wikipedia, the free encyclopedia.