Much of the international and national research on ability grouping agrees that schools that track students into academics based on ability unintentionally widen the gap between high and low performers. Therefore, it would seem that if tracking increases the achievement gap, then detracking schools would be an easy sell to parents and educators. Not necessarily so.

The 2006 report Explaining Student Performance, commissioned by the European Union and conducted by independent research center The Danish Technological Institute, concludes that heterogeneous grouping in Nordic countries helps all students, and does not hurt high achievers. The majority of recent research on ability grouping concludes that schools using tracking systems worsen disparities between high- and low-performing students, creating more academic segregation, with more poor and minority students being shunted into the lowest tracks.