I use the following standard Computer Science Department guidelines (for MSc modules) for determining grades on continuously assessed work.

COMP519 marking descriptors

GradeClassificationPercentage Qualitative Description
A*Good Distinction80+Factually almost faultless; perceptive and focused treatment of all issues. Clearly directed; logical; comprehensive coverage of topic; strong evidence of reading/research outside the material presented in the programme; substantial elements of originality and independent thought; very well written. critical and scholarly presentation.
ADistinction70-79Logical; enlightening; originality of thought or approach; good coverage of topic; clear, in-depth understanding of material; good focus; good evidence of outside reading/research; very well written and directed.
BGood Pass60-69Logical; thorough; factually sound (no serious errors); good understanding of material; evidence of outside reading/research; exercise of critical judgement; some originality of thought or approach; well written and directed.
CPass50-59Worthy effort, but undistinguished outcome. Essentially correct, but possibly missing important points or inadequate treatment. Largely derived from material delivered in the programme, but with some evidence of outside reading/research; some evidence of critical judgement; some weaknesses in expression/presentation.
DCompensatable Fail40-49Incomplete coverage of topic; evidence of poor understanding of material; Poor presentation; lack of coherent argument. Very basic approach to a narrow or misguided selection of material. Lacking in background and/or flawed in structure.
FFail< 40Serious omissions; significant errors/misconceptions; poorly directed at targets; evidence of inadequate effort. Shallow and poorly presented work showing failure in understanding.