In "Flowers for Algernon", why do you think it is important for Charlie to write down every thing that happens to him?

In the novel "Flowers For Algernon," Charlie Gordon is a science experiment.  Algernon is a mouse that is involved with Charlie as another part of the same experiment.  Charlie has an IQ of 68 and he is operated on to try and increase his intelligence level.  Algernon, the mouse, is also undergoing the same treatment as Charlie.  It is important for Charlie to write everything down as it happens to him so the doctor's in charge of the experiment will have specific data to record Charlie's progress or his lack of progress.  Their whole concept is to write a paper, succeed at their experiment and then get rich.  Without Charlie's data they have not basis for their reports.  Charlie has the surgery, improves, and then deteriorates back to his original IQ.  He indeed kept a journal and the novel  is told from Charlie's point of view.