Total grit scale score does not represent perseverance

In PNAS, Jachimowicz et al. (1) claim that the results from a three-study investigation show that passion moderates the perseverance–performance relationship such that the relationship is stronger when passion is high. Their metaanalysis (study 1) is characterized by a series of questionable decisions and coding errors, but my primary concern is that the findings of all three studies are based on a statistical error. Because of space limitations, I focus this letter only on this primary concern. The two grit scales (2, 3) were developed to measure two aspects … [↵][1]1Email: mcrede{at}iastate.edu. [1]: #xref-corresp-1-1