Turns out that grittier kids were significantly more likely to graduate, even when I matched them on every characteristic I could measure, things like family income, standardized achievement test scores, even how safe kids felt when they were at school.
Det vise sig, at viljefaste børn havde væsentligt større sandsynlighed for at bestå, selv da jeg matchede dem på ethvert træk jeg kunne måle, som familieindkomst, standardiseret test scorer, selv hvor trygge børn følte sig, når de var i skole.