The personality construct of 'sociosexual orientation' or short 'sociosexuality' describes interindividual differences in the tendency to engage in sexual relationships without deeper emotional committment. Since Simpson and Gangestad (1991) introduced the Sociosexual Orientation Inventory (SOI) as an economic measurement instrument, this construct is popular in personality and social psychology, as well as in sexuality research and evolutionary psychology. We (Penke & Asendorpf, 2008) developed a revised version of the SOI, which did not only correct several psychometric problems of the original that have often been criticized, but which also alows for the separate assessment of three facets of sociosexuality: behavior, attitude, and desire. Studies have shown that this differenciation of the construct is highly advisable, since the three facets often show very distinct relationships with other variables.
On this site you can find the official English items of the SOI-R. Please feel free to use them in your research! In addition, you can find a short manual (incl. item keys) and norms for the SOI-R.
A note on scoring the SOI-R: Sociosexuality is a dimensional construct and thus measured continuously with the SOI-R. There is no natural cut-off for a categorization of individuals as "restricted" vs. "unrestricted". I strongly recommend that you analyze SOI-R data dimensionally.
The SOI-R is now available in 25 different languages (click here).
The most important reference for the SOI-R is:
Penke, L., & Asendorpf, J. B. (2008). Beyond global sociosexual orientations: A more differentiated look at sociosexuality and its effects on courtship and romantic relationships. Journal of Personality and Social Psychology, 95, 1113-1135.