Each professor will have his or her own way of marking your essays and providing feedback. The following is a list of commonly used marks that indicate specific issues or problems in writing. Please be aware that your professor may use different marks or use the same marks to mean something else. When in doubt, always ask your instructor.

The marking system below uses, for reference, Susan Thurman’s The Only Grammar Book You’ll Ever Need, an inexpensive, concise, and clear guide to grammar and style.

Download a pdf of the Error Notation System here.