empirical data

I know that it is hard to collect empirical data on something as subjective as writing, but I still think it would be valuable to the research we've read. In Coogan, I would have liked to see figures (or a graph or something) about how many students specifically emailed in, how many "disappeared" when the conversation went not as planned, and how many were deemed "successful" tutoring sessions. Defining all those terms would be tricky, yes, but it seems like all our authors have been selective about what studies they detail, and this weakens their arguments. Rather than accepting the study fully and discussing its strengths, as a class, we seem to criticize first, and the criticisms come from "holes" that we notice. I think this could be fixed with a few simple, clear graphs and charts that represent the numbers.