Much of the success on an essay test comes not during the test time but in the preparation time. If you know the material, you'll be able to generate your lists and notes quickly to help you write complete answers. If you fully understand the theory that a test question asks you to apply, then you'll be able to make coherent connections between theory and application. If you understand the specialized terminology being covered on a test, you will not only understand the questions more quickly, but you'll be able to use the jargon appropriately to write professional responses. Teachers know when students are padding responses to avoid answering a question, so writing skills can't carry you through a testing situation if you don't know the content.