Mindfulness is defined inconsistently, and its various measures resemble established personality self-report scales. Therefore, jingle and jangle fallacies are likely to undermine the construct’s utility. To address these issues, we conducted two studies to test three hurdles of validity: 1) a sound definition and measurement model, 2) empirical distinctiveness, and 3) incremental criterion validity. We established an overarching and inclusive mindfulness definition covering twelve aspects. Based on this definition, we used an item sampling algorithm to select items from eight mindfulness scales. We established an eclectic bi-factor and a single-factor model, both fitting the data well. Bivariate latent variable correlations between a single mindfulness factor and big-five/six personality factors reached up to .68. Although 50% of mindfulness' variance was unaccounted for by the personality factors, it provided no meaningful incremental criterion validity over personality factors. Our results indicate that mindfulness has little or no incremental utility above established personality factors.

Personality inventories are predominantly curated using factor analytic approaches. Indicators capturing common and thus redundant variance are preferentially selected, whereas indicators capturing a large proportion of unique variance outside the broad trait domains are omitted from further research. Even recent research dealing with lower-level personality traits such as facets or nuances has invariably relied on inventories founded on this factor analytic approach. However, items can also be selected to ensure low instead of high communality amongst them. The expected predictive power of such item sets is higher compared to those compiled to capitalize on the indicators’ redundancy. To investigate this, we applied Ant Colony Optimization (ACO) to select personality-descriptive adjectives with minimal inter-item correlations. When used to predict the frequency of everyday life behaviors, this ‘crude-grit’ set outperformed a traditional big-five item set and sets of randomly selected adjectives. The size of the predictive advantage of the crude-grit set was generally higher for those behaviors that could also be predicted better by the big-five item set. This study provides a proof-of-concept for an alternative procedure for compiling personality scales, and serves as a starting point for future studies using broader item sets.