Invariance of Spanish version of Sexual Double Standard Scale across sex, age, and education level

Background: The Sexual Double Standard Scale (SDSS) is one of the most widely-used scales for evaluating the Sexual Double Standard (SDS) and the Spanish version of the scale displays adequate psychometric properties in the adult Spanish population. The aim of this study is to examine the factorial invariance and differential item functioning (DIF) of the Spanish version according to sex, education level, and age, with the objective of describing and comparing SDS based on these variables. Method: A sample of 3,838 heterosexual participants was used (1,908 men and 1,930 women) between the ages of 18 and 90. Results: The results showed that the factorial structure of the SDSS is invariant in terms of sex and education level; with none of these items displaying DIF. Only items 11 and 14 display DIF in terms of age and, therefore, it is recommended that these items be excluded when making comparisons between age ranges. The association of SDSS with sex, education level, and age follows the expected results. Conclusions: The Spanish version of the SDSS is invariant and, as a consequence, can be used in different types of samples.