The Revised GRE test is a section adaptive test, this means that the first section of the Quantitative or Verbal section is of average difficulty, and the difficulty level of the subsequent section depends on how well one does in the first section.
ETS rates the test questions with a difficulty level ranging from 1 to 5, 1 being the easiest and 5 being the most difficult. In the first section, the weighted average of the difficulty of the questions is close to 3. The section consists of a mix of easy, medium, and difficult questions. The number of incorrect questions in the first section determines the difficulty level of the subsequent section. This format of test administration is called section adaptive.
To find out the impact of the difficulty level of questions missed on the overall score, I used the PowerPrep II 2.1 software and ran the following tests:
Trial#1: Miss 3 of the easiest questions in the first quantitative section, and then miss 3 of the easiest questions in the second section as well.
Trial#2: Miss 3 of the hardest questions in the first quantitative section, and then miss 3 of the hardest questions in the second section as well.
In both of the above trials, the second section was identical, and of the highest difficulty level. This is because I only missed three questions, if I had missed a greater number of questions, the difficulty level would have been different for the second section. I will do additional trials to show the relationship between the number of questions incorrect in the first section and the difficulty level of the second section. The key point of this observation is that the difficulty level of the second section is entirely dependent on the number of questions missed in the first section, and not on the difficulty level of the individual questions.
The interesting outcome is that in both of the trials, the final quantitative score was 162 (84th percentile). In both cases, the two sections were identical and I missed a total of six questions. However, in one case I missed the easiest questions and in the other I missed the hardest questions. This means that the final score(assuming the sections are of the same difficulty level) purely depends on the number of incorrect questions, and not on the difficulty level of the individual questions.
So how does all this information help a GRE test taker. I recommend that when you are attempting the first section, focus on the easiest questions first and make sure you get those right. Only then move on to the hard ones. Because one can jump from one question to another, it is best to first target questions that are easier and are on topics that you can tackle with ease. Once you have completed those questions, then move on to the harder questions. This is prudent because all questions are equally weighted when it comes to deciding the difficulty level of the second quantitative section. The same strategy should also be implemented in the second section.
The final score is then computed by an equating process that takes in to account the difficulty level of each section administered to a student and the number of questions correct in each section. For example, the average difficulty of the question in the actual Revised GRE test I took was 3.2 for the first quantitative section and 4 for the second section. The final score would then depend on the number of questions that you missed. In my next, blog post I will present results from further trials that show the impact of number of incorrect questions on the overall score.