Hi Omid,
I figured I would provide you some basic information on the scoring system:
The scoring of the GMAT may seem complicated. Here is an overview of how this works. You can find out more at the website of GMAC, the organization that administers the GMAT.
Firstly, here is how the test is structured. There are four sections in the following order:
1. Analytical Writing Assessment (AWA) \ 1 Argument essay \ 30 minutes
2. Integrated Reasoning \ 12 questions on four question types \ 30 minutes
3. Quantitative section \ 37 questions \ 75 minutes
4. Verbal section \ 41 questions \ 75 minutes
The AWA has a maximum score of 6 (in intervals of 0.5); the IR, a maximum score of 8 (in intervals of 1) and the Verbal and Quant are both scored separately on a scale of 60 (in intervals of 1). There is also a total score reported from just the Verbal and Quant tests together, which ranges from 200 to 800 (in intervals of 10). This combined score is scaled from the individual Quant and Verbal scores.
It is important to remember that the Verbal and Quant tests on the GMAT are computer-adaptive tests (CAT). In a CAT, you are initially presented with a question of medium difficulty and the test system will present you with easier questions if you get the previous questions wrong and harder questions if you get the previous questions correct. The questions are weighted, with the harder questions giving you a higher score than the easier ones. The scoring in these CATs is via a complex algorithm that GMAC do not publish. So please do remember that 1 exam does not fully tell the tale of one's true scores. Averaging out about 4 or 5 exams should be more indicative. Many other factors may come into play too including how many mistakes one makes in a row, whether one has left out questions at the end, and even perhaps one's pacing and whether one guessed the last bunch of either section. These can affect score as can the psychological state of the test taker on a particular day.
To illustrate, one can take a GMAT exam on 5 consecutive days and in each one score, for example, 50% correct yet get a score out of 60 ranging from 15 to 35 or so. This has been tested and indicates that it is not necessarily about the number of correct or incorrect but rather about what question one gets right along with the factors listed above.
Also, note that not all of the GMAT questions will contribute to your score. Roughly one quarter of the questions (9 on the Quant and 11 on the Verbal) will be experimental questions that are being road-tested. You will not be able to tell which ones these are and they may be easy or difficult. So you should not assume that you just got a question wrong, if you are suddenly presented with a very easy question.
In addition to the scaled scores, each score is coupled with a percentile ranking. These compare each of your scores with the scores obtained by other GMAT test-takers. For this reason, whilst your scaled scores are fixed for any time you took the GMAT, your percentile ranking will change every year depending on how well the other students did in all the GMAT tests in the last three years.
You may also wish to take a look at our blog for additional information.
I hope this helps a bit.
Sincerely,
Evan