david, great questions and I look forward to reading all the responses. For me there has always been a distinct and direct relationship between knowing my students and the grouping process I have used. For groups that know each other well I tend to allow partners to self select but if the outcomes are not being achieved then I will change things up. If the classroom is totally new to each other then I use a more random method such as counting by 2 or 3 depending on how many are in each group. Since friends tend to sit close to each other this will split them up so this is why it is important to know as much about your students as possible. For me it is really about the outcomes and if I have groupings that are successful then I may not switch things out for a long time. James Jackson