Research on what makes good writing instruction

There’s not a lot of quality research on good writing, but a recent report summarized the finding of 14 high-quality studies.  Here’s an article about the research and here’s one really interesting finding (my underline): 

Beyond a well-structured writing course, Slavin and his colleagues noted that in these studies of writing, the classes were “exciting, social and noisy.”

“Motivation seems to be the key,” Slavin and his colleagues wrote. “If students love to write, because their peers as well as their teachers are eager to see what they have to say, then they will write with energy and pleasure. Perhaps more than any other subject, writing demands a supportive environment, in which students want to become better writers because they love the opportunity to express themselves, and to interact in writing with valued peers and teachers.”