Yes, for some children, I think that paring elementary school students in classrooms can be effective. Some children learn better with others and some are lone learners. Either way pair the students with other students enhance their social skills and their ability to work well with others. It can be an all around good experience for both students.
Learning strategies that involve pairing elementary school students in classrooms may be effective for certain students. However, we should note that these may not be effective for all students. When it comes to the pairing we should see if it is effective for each student. If it is not effective for them then they should not do it.
Learning strategies that involve pairing two students together fosters cooperation and social skills among elementary school students. Plus, it makes teacher supervision of students a little easier. Instead of 30 students, there are 15 pairs. These strategies don't necessarily gauge what grades kids should get, but pairing students together helps kids learn other skills that go beyond a letter grade.
I believe that pairing elementary school students in classrooms is an effective learning strategy. This is especially true when a student with a disability is paired with a typical peer. The student with a disability will not be embarrassed by what he or she may not know and both students can learn to work together. Also, like the saying goes, "two heads are better than one," and I think that is true with students because using their combined knowledge can be beneficial to both.
It really depends on how often students are being paired and how it's being done. Are students made to pick their own partners or are they assigned partners by the teacher? Are students given the option to work alone if they wish to? (I feel that should be an option 75% of the time; some kids work best independently, and a lot of teachers at the elementary level seem to have trouble acknowledging that.)
Regardless, I think there are a lot of teachers who overdo it. Long-term projects offer up a great chance to teach students the importance of collaboration, but it seems unnecessary to have them pair up for smaller assignments. Best case scenario, it gets done a little quicker; worst case (and most likely, at least when I was younger) scenario, the classroom gets rowdy as the conversation strays away from the task at hand and students are unable to focus. Besides, elementary schools generally give students ample time to socialize, whether it's during recess and lunch or special classes like gym, music, and art.
The real problem is that the majority of elementary schools have the same twenty or so kids in the same room for the whole year, which means for some students who may only have a handful of good friends in their grade, class placement can make or break their year socially, and even when you do have friends in your class, being around the same gaggle of kids day in and day out grows stale. Having elementary schoolers (except for kindergarteners and maybe first graders) switch classes throughout the day puts them in a better position, both academically and socially. A science teacher is generally going to put together a more effective lesson plan than would one teacher who's juggling science, social studies, math, and reading, for example. And not only would kids be made to interact with a wider range of people who they, in the traditional elementary school classroom, might not have met, but they'd also learn how to meet new people and deal with change-- and that's a lot more beneficial to their social development than simply having them partner up for a worksheet.