Abstrakt
The Satisfaction with Life Scale (SWLS; Diener et al., 1985) is one of the most commonly used tools for measuring life satisfaction and subjective well-being. Many studies using Classical Test Theory have confirmed its good psychometric properties including validity, internal consistency, test-retest reliability (Pavot et al., 1991; Lucas et al., 1996; Pavot & Diener, 1993), however results regarding its dimensionality are varied (for an overview, Emerson et al., 2017).
Furthermore, only few studies testing their modification (e.g. Kjell & Diener, 2020; Vitterso et al., 2005).
In the Czech Republic except for one old study testing its psychometrics properties on a small sample of university students (Lewis et al., 1999) the SWLS has not been tested yet. The aim of this article is to test the psychometric properties of the Czech version of the traditional SWLS consists of five items and compare the results with their abbreviated version with four (SWLS-4) and three items (SWLS-3) by using Item Response Theory Analysis.
Application of IRT can also reveal if a shorter response scale can be applied. For analysis, data from a representative sample of the Czech population older than 18 years are used (N = 1,000).
The results showed that both abbreviated versions of the SWLS demonstrate very good psychometric properties as well as a shorter response scale and therefore can be used interchangeably without affecting its psychometric qualities. This research is very beneficial for all researcher in this area because using short scales can be useful especially in online surveys.
Moreover, in the Czech Republic, this is the first testing the SWLS using IRT, which is not widely used method here.