Short Dark Tetrad - Polish version (SD4-PL): adaptation and extended psychometric evaluation of a measure of subclinical psychopathy, narcissism, Machiavellianism, and sadism.

The Short Dark Tetrad scale (SD4) is a brief self-report instrument designed to assess four socially aversive or antagonistic personality traits: subclinical Machiavellianism, narcissism, psychopathy, and sadism. The purpose of the present study was to provide an extended psychometric evaluation of the Polish version of SD4 (SD4-PL). Following translation and cultural adaptation of the 28 original items, data were collected using an online survey. After data screening, the final analytic sample comprised 931 Polish adults (mean age = 34.64 years, SD = 10.98; 76.8% women). To provide a comprehensive psychometric evaluation, the validation strategy combined split-sample exploratory and confirmatory factor analyses, ordinal CFA with WLSMV estimation, comparisons of one-factor, correlated four-factor, higher-order, bifactor, and merged-factor models, item-level diagnostics, internal consistency coefficients, convergent and discriminant validity indices, direct validation of the sadism subscale with the Comprehensive Assessment of Sadistic Tendencies (CAST), and an exploratory assessment of gender invariance. The correlated four-factor model showed partially acceptable fit in the full sample (CFI = .926, TLI = .919, RMSEA = .082, SRMR = .085) and was broadly replicated in the holdout sample. The bifactor model provided the strongest fit (CFI = .959, TLI = .952, RMSEA = .063, SRMR = .067), suggesting that SD4-PL scores reflect both specific dark/antagonistic traits and a broader common antagonistic core. Reliability was acceptable for narcissism, psychopathy, sadism, and the total score, although reliability for Machiavellianism was weaker (alpha = .67, omega = .68). The sadism subscale showed strong convergent validity with the CAST total score (r = .661). The SD4-PL may therefore be useful as a brief measure of dark/antagonistic traits in Polish-speaking adults, but interpretation of individual subscales, especially Machiavellianism and gender comparisons, should remain cautious.