A C answer fails to address (or does so inaccurately) major dimensions of the question or the assigned materials related to it, B: The answer demonstrates that the student has a solid understanding of and can clearly explain most or all of the relevant concepts and assigned materials relevant to the question.
A B answer accurately defines most or all of the question's key concepts and explains their relationship to major class topics.
An A answer goes beyond correctly defining the question's key concepts and accurately explaining their relationship to major class topics.
An A answer also provides numerous examples and specific references to course readings and seminar discussions, indicating that the student thoroughly understands and can apply the concept/term and support arguments with the best available evidence.
In many of my courses, students take in-class tests with essay and true-false items.
I use these questions to assess how well students understand important course concepts and to see how well they can analyze and apply evidence in ways that demonstrate their mastery of course materials.
The less obvious downside, which comes from my colleagues in the education community, is that multiple choice tests are very limited in their ability to measure learning.
They are very good at seeing if students can regurgitate memorized facts; they are really poor at determining whether they can integrate and use those facts. What is the difference between a “B ” and an “A-” paper or “C-” or “C” essay answer?
I assign grades to open-response items using the following assessment criteria: F: The answer does not meet college-level expectations for quality of work.
The answer is either left blank or completely wrong in a way that indicates that the question's key concepts/terms are not understood at all by the student.