By departmentalizing 2nd and 3rd grade, do you mean combining the two grade levels? Most parents and teachers do not like combination classes. However, funding is so tight for many schools that the adminsitration is constantly looking for cost cutting options. I am aware of one study. This study found no loss in student achievement resulting from combination classes. See reference below.
My principal wants one teacher to teach Reading to both the 2nd grade and 3rd grade classes, another to teach Math, another to teach just writing and then one to teach just Science. Thanks for the link. I will check it out!!
This may not be a bad idea. Sometimes when teachers specailize, they invest more time in planning and executing great lessons. Hopefully, they will organize some ability groupings, or have other ways to differentiate the instruction. It is important that the 3rd grade students and especially the 3rd grade advance students continue to advance at an appropriate level.