How to measure the self-determination continuum? Initial validity evidence for the polish version of the Global Motivation Scale (GMS)

The Global Motivation Scale (GMS) is an 18-item self-report questionnaire. It measures a multidimensional conceptualization of motivation that falls along the self-determination continuum. The aim of the study was to evaluate the psychometric properties of the Polish version of the GMS, and to investigate its structure and reliability in a group of 537 subjects, aged 18-86 (M = 36.19; SD = 15.20). The bifactor modelling didn't validate the theoretical six-factor model of the GMS, thus an exploratory analysis was conducted to determine an optimal model across age, gender and education. The adopted four-factor model matched three original GMS subscales: intrinsic motivation, external regulation and amotivation; the fourth factor represented identified and integrated regulations simultaneously (introjected regulation wasn't included). Correlations among the factors didn't confirm the simplex pattern, while the composite reliability coefficients were low (.55-.66). It is insufficient to analyze the assessment of the self-determination continuum only for statistical correctness - linguistic and cultural contexts should also be considered.