Designed to use recent research on revision activities and personal error analysis, a classroom study compared grades on papers written by students with and without specific instruction and practice in revising and proofreading techniques. Detailed statistical analyses of two writing assignments revealed no significant difference in grade achievement between the revision and the nonrevision groups. In addition, although 89% of the students receiving an "A" grade on first drafts in the revision group rewrote their papers four out of five possible times, only 58% of the whole revision group did more than a minimal rewrite on their first draft. These findings suggest that average or below average students may have needed more time to revise than was allotted in the program and that grades were not a motivating factor in revisions. While not producing concrete evidence of the benefits of revision, the experiment suggests that discovery revision activities and proofreading and editing heuristics are helpful, even if not absolutely necessary, for stronger writers. (MM)