Psychometric evaluation of the full and shortened versions of the WGCTA-II in Slovak university students

Critical thinking (CT) is a key cognitive skill essential for academic and informed decision-making. Although the Watson-Glaser Critical Thinking Appraisal (WGCTA) has been widely used internationally, its psychometric properties have not yet been systematically evaluated in Slovakia. The present study aimed to examine the reliability and validity of the Slovak WGCTA-II (Form C) and to develop a shortened version using contemporary psychometric methods.

Slovak university students (N = 264) completed the WGCTA-II and two versions of the Cognitive Reflection Test (CRT-V, CRT-N) for criterion validity. Reliability analyses, confirmatory factor analyses (CFA), parallel analysis, and Item Response Theory (IRT) models were used to examine internal consistency, dimensionality, and item functioning. Based on theoretical relevance and psychometric performance, two core dimensions-Interpretation and Evaluation of Arguments-were retained. An independent sample (N = 137) was used to replicate reliability and model fit.

The original WGCTA-II showed acceptable overall reliability but limited construct validity at the subscale level. The resulting 9-item unidimensional version demonstrated good IRT model fit (RMSEA = 0.042; SRMR = 0.076) and satisfactory reliability (ω = 0.66), replicated in the second sample. Criterion validity was supported by correlations with the Cognitive Reflection Test (r = 0.30-0.38).

These findings provide the first psychometric evidence for the Slovak WGCTA-II, demonstrate the utility of combining CTT and IRT for robust test evaluation, and introduce a concise, culturally adapted tool for efficient assessment of critical thinking, contributing to methodological innovation in psychological measurement.