We tested the hypothesis that underrepresented students in active-learning classrooms experience narrower achievement gaps than underrepresented students in traditional lecturing classrooms, averaged across all science, technology, engineering, and mathematics (STEM) fields and courses. We conducted a comprehensive search for both published and unpublished studies that compared the performance of underrepresented students to their overrepresented classmates in active-learning and traditional-lecturing treatments. This search resulted in data on student examination scores from 15 studies (9,238 total students) and data on student failure rates from 26 studies (44,606 total students). Bayesian regression analyses showed that on average, active learning reduced achievement gaps in examination scores by 33% and narrowed gaps in passing rates by 45%. The reported proportion of time that students spend on in-class activities was important, as only classes that implemented high-intensity active learning narrowed achievement gaps. Sensitivity analyses showed that the conclusions are robust to sampling bias and other issues. To explain the extensive variation in efficacy observed among studies, we propose the heads-and-hearts hypothesis, which holds that meaningful reductions in achievement gaps only occur when course designs combine deliberate practice with inclusive teaching. Our results support calls to replace traditional lecturing with evidence-based, active-learning course designs across the STEM disciplines and suggest that innovations in instructional strategies can increase equity in higher education.

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We describe a new species of treefrog of the genus Ptychohyla from southern Mexico occurring to the east of the Isthmus of Tehuantepec. This new species can be distinguished from Mexican congeners by a combination of a pale pink iris and the presence of nuptial excrescences in breeding males. Including this new taxon, the number of species of Ptychohyla increases to 14, with seven of these occurring in Mexico. The new species is relatively common in pristine tropical forests, but appears to be sensitive to habitat degradation and has not been found in human modified habitats, suggesting that habitat modification is a threat for this hylid frog.