High-calibre students are sometimes described as the ¡°rocket fuel¡± that powers research universities to world-class status.?But less talented students should not hope to benefit too much from living alongside more intelligent peers, research suggests.

In fact, students¡¯ grades may actually go down if they share the same social space as brainier students, according to a study by Ahmed Rahman, associate professor of economics at the United States Naval Academy, in Annapolis, Maryland. High-achieving learners¡¯ success rubbed off on those around them only if the students actually took classes together.

In the , presented at the Royal Economic Society¡¯s annual conference, which ran from 10 to 12 April, Professor Rahman tracks the performance of 20,000 students at the national academy on compulsory courses.?Because the students had no control over who they lived with or who they studied with, differences in peer effects could not be explained by students choosing particular friends or courses.

Students who lived with high performers had slightly worse grades than would be expected: a 100-point increase in the average verbal SAT (college admission) score of housemates typically reduced a student¡¯s course grade by 0.16 grade points on a four-point average scale, according to the study.

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However, when their classmates are high performers, the peer effect became positive ¨C with course grades rising by 0.16 grade points when a student is surrounded in class by those with higher SAT grades.

While the effect on grade performance is relatively small in both cases, the results are nonetheless ¡°startling¡± given the consistency in which the effect is observed across the cohort, says Professor?Rahman.

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It debunks the idea that high academic achievement can simply ¡°rub off¡± on undergraduates living in the same environment ¨C in this case, ¡°company¡± dormitories of about 150 trainee officers who are randomly assigned to their respective living quarters.

¡°In broad social settings, students of like characteristics tend to interact more with each other, so higher ability students can drive average students away from them and worsen academic performance,¡± says Professor?Rahman.?¡°But in more task-oriented groups, students are more willing to overcome differences and work together.¡±

The study may help to reconcile some of the ¡°wildly inconsistent¡± findings around peer effects over the years, says Professor?Rahman.

Some education scholars have asserted that mixing ability groups drives up overall performance, particularly among mediocre students who can learn from better classmates. However, others point to studies that recommend more selection-based stratification.

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¡°Policymakers should take note: just throwing smarter students in the group can backfire and make overall performance worse,¡± said Professor?Rahman.

jack.grove@timeshighereducation.com