Advantages of essay questions
The essay, however, requires much less preparation. The student must suuply rather than select the good response. To garner the full benefits of including essays on your tests, you must allot sufficient time to read and comment on the students’ responses. If you take Bloom literally, can’t really test "knowledge" because by definition their ability to incorporate into an essay takes you up a couple of steps to application — though I suppose it would be possible to count objectives like "naming" as "knowledge" but relatively few opportunities in essay
Only use essays when essays are called for