Abstract
Satisfaction With Life Scale (SWLS; Diener et al., 1985) is one of the most used tools for measuring life satisfaction and subjective well-being. Most studies using Classical Test Theory (CTT) have confirmed the good psychometric properties of the SWLS, including validity, internal consistency, and test-retest reliability (Pavot et al., 1991; Lucas et al., 1996; Pavot & Diener, 1993).
However, the results regarding its measurement invariance, and especially dimensionality, vary (e.g. Emerson et al., 2017).
Nevertheless, only a few studies have tested the modifications of the SWLS (e.g. Kjell & Diener, 2020; Vitterso et al., 2005).
The SWLS was tested in many countries worldwide, but not in the Czech Republic, except for one old study testing its psychometric properties on a small sample of university students (Lewis et al., 1999). Based on the results of exploratory and confirmatory factor analysis, which showed high consistency of the SWLS, it is recommended to use the Czech translation of this scale in surveys of the Czech population.
Although more than twenty years have passed since the study, no methodological research on the SWLS in the Czech Republic has not been realized so far. The main aim of this paper is present the results of study, that examined psychometric properties of the Czech version of the original SWLS comprising five items, and its abbreviated versions with four (SWLS-4) and three items (SWLS-3) using Item Response Theory (IRT).
By applying IRT, we can also reveal how the seven-point response scale works and whether a shorter scale can be used. The analysis was performed on data from October 2019 from a representative survey of the Czech population over 18 years of age (N = 1,000).