Please note that this is simply a guideline to grading, not a fixed policy. Keep in mind that there is no single kind of "B" paper, for example, and that a number of variables figure into any evaluation of a given paper. I've listed the grades from lowest to highest not because I'm pessimistic, but because I want you to read all of the descriptions, not just the "A" description.
An "F" Paper
An "F" paper simply doesn't work. It has no thesis directing it, and lacks even a minimal coherence. The writing may fail on a sentence level (in other words, individual sentences are incoherent) It reflects little knowledge of the text
If you receive an "F" paper, come see me immediately. I can help you. Do not despair.
A "D" Paper
Think of a "D" paper as a "C" paper that doesn't work. A "D" paper tries to delineate an argument with a coherent outline, but does not make its point sufficiently clear. The thesis may be vague or unsupported, and it may not move beyond plot summary (remember, a successful paper must make an argument, not merely demonstrate that the text has been read.) The paper may lack important factual information, and may suffer from logical gaps. Remember: a grade of "D" or "F" is not an assessment of the writer's intelligence; it is a measure of how successful the paper is at conveying an argument about a particular topic. The grade is on the paper, not on the student.
A "C" Paper
A grade of "C" reflects adequate college work. A "C" paper demonstrates a firm grasp of the obvious but doesn't move very far beyond that point. The thesis is a general statement or an obvious point in the text, the argument coheres but is simply structured (i.e., it doesn't explore any secondary arguments). There is adequate support for the assertions in this paper, and supporting quotations are adequately explained. Sentence structures are not especially sophisticated, but they are free from serious errors in grammar and punctuation.
A "B" Paper
A "B" paper is more than merely adequate. This paper has a strong sense of unity, for it grows out of a tightly focused thesis. The thesis demonstrates some insight and original thinking on the part of the writer. The argument is carefully arranged and fully developed; supporting evidence is appropriate and well-integrated. A "B" paper will often explore secondary arguments or address possible objections to its argument. Sentence structures show some sophistication. Mechanics are sound, and those mechanical problems which exist arise from the complexity of the sentences. (In other words, the mechanical problems in a "B" paper are more sophisticated than those in a "C" paper.)
An "A" Paper
An "A" paper is a "B" paper in which everything works. Complex sentence structures are composed artfully and diction is sophisticated. "A" papers usually exhibit creative use of figurative language. An "A" paper makes an insightful argument with force and clarity. It combines subtlety of thinking with linguistic and rhetorical excellence. An "A" paper is a real accomplishment.