With school returning to something closer to normal after over a year of disruption, most principals are looking for ways to get students back on track. Recent research suggests surprising benefits to student outcomes from a relatively straightforward policy: keeping teachers in their current grade and subject assignment to the extent possible.
Teachers, just like students, learn by doing, and those teaching 5th grade for the second time will most likely be better at teaching that grade than they were the first time. Switching them to a new grade loses the benefit of that learning.
Moreover, teachers new to a grade level can disrupt the existing team. Grade-level teacher teams learn to work together. Put a new person on the team, and the team has to relearn its collaboration routines. Plus, veteran teachers will turn some of their focus from their classroom to helping their new team member.