Testování psychometrických vlastností a ekvivalence české verze Škály spokojenosti se životem (SWLS) pomocí metod konfirmační faktorové analýzy, teorie odpovědi na položku a bayesovského modelování

The Satisfaction with Life Scale (SWLS) is one of the most commonly used instruments for measuring life satisfaction. The aim of this study is to test the psychometric properties of the Czech version of the SWLS using Confirmatory Factor Analysis (CFA) and Item Response Theory (IRT) and to test its invariance between social groups in terms of gender, age, and education using Bayesian modelling on a representative sample of the Czech online population, as the scale has not yet been tested on representative data in the Czech Republic. The research sample consists of 960 respondents aged 18 to 69 years. The results confirmed that the psychometric properties of the Czech version of the SWLS are very good, but, at the same time, it is evident that the fifth item shows worse results than the other four items. In terms of dimensionality, CFA and IRT confirmed its modified singlefactor structure with correlated residuals between the fourth and fifth items as the most appropriate. Testing for approximate measurement invariance using Bayesian modelling showed that the SWLS measures comparably between groups based on gender, age, and education. In conclusion, the Czech version of the SWLS is a suitable, verified, and reliable instrument for measuring the life satisfaction of Czech citizens.