This report, part of the National Assessment of Educational Progress (NAEP) survey, describes one facet of the national assessment of writing. The students--9-, 13-, and 17-year-olds who constitute the sample for the NAEP studies--were told to use their best writing but were not told that their papers would be examined for mechanical correctness. The data on mechanical correctness obtained from an examination of these papers during the 1974 survey are compared with the data obtained from the 1970 assessment. Richard Lloyd-Jones of the University of Iowa (Iowa City) and Ross Winterowd of the University of Southern California (Los Angeles) offered the following observations about the writing assessment results: there is no evidence that the schools must "go back to basics" because the basics seem well in hand; language is always changing, but new ways of writing may not be worse in any defensible sense; writing is inextricably tied to reading; "Edited Standard English" as taught in most schools is one dialect of English; there are fewer rewards for being a good writer; and increasing class size results in fewer writing assignments. (RB) Primary type of information provided by report: Results (Change) (Selective).