Similar problems occur with the assessment of students' writing ability, and the methods that experts have developed over the last 25 years to evaluate it may shed some light on the question of how best to evaluate professors' teaching ability. Teaching and writing are not the same, of course, but both fall between craft and art, are extremely complex and difficult to assess, and have important implications for the people they affect—the students or the faculty members.

The most important concept to emerge in writing assessment has been the development of holistic scoring as a reliable way to assess students' performance on essay examinations. That development, begun under the aegis of the Educational Testing Service in the 1960's, allows raters to give each student essay a single numerical score, in accordance with a brief, focused scoring guide, for the overall quality of the writing. Training in the use of the scoring guide has become so sophisticated that raters give very consistent scores to the same student essays. If two or more raters evaluate two or more samples from the same student, the scoring can be extremely reliable.

The scores are regularly used by admissions officers at colleges and graduate and professional schools, as well as by faculty members who are deciding which courses to place students in, or whether a student has met a writing requirement for graduation.

Holistic scoring of student writing has come under attack, however, because it provides little useful information for teachers, yielding only ratings of performance according to the criteria set out in the scoring guide. That is, a numerical score is fine for placement, but teachers want assessments that will yield more detailed diagnostic information for students in their classes. Teachers need to know if a particular paper's low score results from faulty sentence structure, lack of evidence to support assertions, incoherent paragraphs, misuse of sources, or some other flaw. the mechanics of writing, or prior knowledge of the subject?