Answer: “Also finds that the type of comments matters; comments coded as “problem detection” and “solution suggestion” were positively correlated with posttest writing quality, as opposed to the number of praise comments and the average length of comments.”
Comment: I find this research on teachers comments on writing interesting, especially concerning praise. You have to praise, of course. But the comments that count are those that detect problems and offer solutions to the problems in writing. RayS.
Source: Cho, K., & MacArthur, C. A. (2011). Learning by reviewing. Journal of Educational Psychology,
Title: “Annotated Bibliography of Research in the Teaching of English.” Richard Beach, et al. Research in the Teaching of English (November 2011), Internet. http://www.ncte.org/journals/rte/issues/v46-2.