First off - Your score is not a percentage!
Varying Difficulty and Scoring of Questions
Exam Structure and Weight Allocation:
The scores for the AUD, FAR and REG sections of the exam are a weighted combination of the scores from the multiple-choice questions (60%) and task-based simulations (40%). The score for the BEC section is a weighted combination of the scores from the multiple-choice questions (85%) and written communications (15%).
Think of the MCQ and the TBS/WC as two separate exams. The grades of each are combined (per the above weights) to form your overall score. On all four exams, the MCQ is more heavily weighted than its counterpart.
Although one would think that answering 75% of the MCQ correctly and scoring 75 or better within the TBS/WC would combine for a passing grade, this is not the case due to the pretesting of questions and the varying point values assigned to each question.
Regardless of which exam you are taking, you are going to be answering many questions that will not be graded, and thus have no effect on your score. These pretested questions are in a sense the AICPA doing their homework, as the questions are being evaluated for future use on the exams. Pretested questions are indistinguishable from the questions that are being graded; thus you must put your best foot forward on every question you encounter on the CPA Exam.
On the AUD and FAR section, 15 of the 90 multiple choice questions and 1 of the 7 TBSs are pretested.
On the REG section, 12 of the 72 multiple choice questions and 1 of the 6 TBSs are pretested.
On the BEC section, 12 of the 72 multiple choice questions and 1 of the 3 WCs are pretested.
Varying Difficulty and Scoring of Questions:
Perhaps the most complex factor in understanding how your CPA Exam is scored lies in the scoring of each individual question. Not all questions are as difficult as their counterparts, and as such, each question is assigned a different value. Through the statistical analysis of candidate responses, the difficulty level of each question is determined and given a numeric value. The more difficult the question, the higher the questions value. Therefore, a candidate who correctly answers 10 difficult (higher value) questions would score more than a candidate who correctly answers 10 easy (lower value) questions.
Specific to the multiple choice portion of the exam, testlets are classified as either medium or difficult based on the average difficulty of the questions within the testlet. The first testlet you receive will always be of medium difficulty. If you perform well on the first testlet you will receive a more difficult second testlet; while those who do not perform well on the first testlet will receive a second medium difficulty testlet. The difficulty of your third testlet will depend on your performance within the first two testlets.
*Multi-Stage Testing is not used within the task-based simulation or written communication portions of the exam. Additionally, your performance within the MCQ will not impact which TBS/WC you receive.
As a result of the above four factors, it is not possible to compute your score on the CPA Exam based on the number of questions you answer correctly. Conversely, there is a chance that one might be able to predict the quality of their performance on the first and second testlet of MCQ by gauging the difficulty of the testlets that follow.
To read more about the CPA Exam grading process visit AICPA Psychometric and Scoring.
Craig Cuthbert, CPA