Strong evidence that sorting students into more homogeneous groups is beneficial, particularly for sorting by previous testing score …

„We find strong evidence that sorting students into more homogeneous groups is beneficial, particularly for sorting by previous testing score. […] This is consistent with the hypothesis that dividing students into more homogeneous groups allows teachers to direct their focus to a more narrow range of students and meet the needs of their particular classroom more efficiently.“

Courtney A. Collins, „Does Sorting Students Improve Scores“ (2013), S. 19f