There is an overwhelming amount of research regarding homogeneous and heterogeneous grouping in education. The former refers to the practice of grouping "like" students together (regarding age, ethnicity, gender, ability, etc.), while the latter refers to the practice of grouping "unlike" students together.
My particular interest is to compare these practices restricted to as many of the following points as possible:
- Undergraduate mathematics education
- Small, intra-classroom groups
- Grouping based on perceived ability (e.g. placement test scores)
Any research (or anecdotes from experienced teachers) approximating this scenario is most welcome.