The Satisfaction with Life Scale (SWLS) has been validated in heterosexual individuals using Classical Test Theory (CTT). The aim of the present study was to analyze the psychometric properties of the SWLS using Item Response Theory (IRT) to address gaps in the existing literature. The original structure comprising five items, as well as an abbreviated version with four items, were examined in a sample of 400 cisgender gay people from Lima, Peru. The results confirmed the unidimensionality of the scale in both versions, which demonstrated adequate psychometric properties with slight differences. Both versions can be used interchangeably without affecting the scale's structure. However, if the objective is to assess more accurately across a broader range of abilities, the 5-item version appears to be superior. Practical implications are discussed."
Herran-Sifuentes et al. (Thu,) studied this question.