SOP is basically a step by step instructions document compiled so that the workers can carry out a complex routine efficiently. I definitely think the SOP’s should be written during research phase. In fact, I used to intern at a lab where we were researching on stem cells. Obviously, the very first time if you are running a procedure it will have its own process. But once you establish a technique/procedure that works and needs to be repeated exactly the same way for different samples, then an SOP is very beneficial. As an intern, I was following a SOP to do certain kind of a protein assay on different kinds of my scaffolds that I used to spin. There was even a SOP for electrospinning the type of scaffold so that it can be used a control and not play as a variable if cells are being seeded on them. Therefore, a SOP is very beneficial during research phase to maintain repeatability and hence accuracy.