Origin
Grit was defined by Angela Duckworth and colleagues as "perseverance and passion for long-term goals" and measured with the Grit Scale (Duckworth, Peterson, Matthews & Kelly, 2007). The original 12-item Grit-O was later refined into the 8-item Grit-S (Duckworth & Quinn, 2009), which improved the measure's factor structure.
Structure
The scale comprises two facets: consistency of interest (not frequently changing goals or being distracted by new pursuits) and perseverance of effort (sustained hard work and finishing what one begins). These combine into an overall grit score, with the perseverance facet generally showing stronger predictive validity than the consistency facet.
Psychometric standing and debate
Duckworth et al. (2007) and Duckworth & Quinn (2009) reported acceptable reliability and predictive validity for outcomes such as educational attainment and retention in demanding settings.
The construct has also drawn substantive critique: meta-analytic work argues grit overlaps strongly with the established Big Five trait of conscientiousness and that its incremental predictive power over conscientiousness is modest (Credé, Tynan & Harms, 2017). An honest reading treats grit as a useful, popular framing of perseverance whose distinctiveness from conscientiousness remains debated.