Love this topic! A few things I'd add:
1) If you can get a question right, get it rightTake a few seconds to double check your work if you know that you're susceptible to silly mistakes. If you know you'll finish but fear that the calculations will take even 30 seconds more than they should, finish them and get the problem right. The reason? On a computer-adaptive test, wrong answers to questions you should get right hurt you more than right answers to questions that really should be above your head help you. Or more simply "easy wrong outweighs hard right". Don't rush through problems just to "save time for harder problems". If you get those moderate problems wrong, you may never see the hard problems; and even if you get them right, there's no guarantee that extra time on a hard problem will mean you get it right.
2) The first 10 questions are very important, but not the way you might thinkThe first 10 questions do have a little extra importance over the last 10 because your results on those first 10 stay with the
DELIVERY system for the rest of that section. Long story short, the adaptive function of the CAT system really serves two functions:
-Scoring (for which all questions count the same)
-Delivery (and here the system uses your results on all previous questions to determine which question to serve you next)
For scoring, question 36 and question 2 count exactly the same. But for delivery, question 2's results are in the system a lot longer - every subsequent question the system delivers you will be impacted to some degree by how you did on question #2.
Now, people overstate the impact of that delivery function and try to game the system by doing everything they can to get the first 10 right. And from that point the scoring system will figure you out...if you get the first 10 right and struggle from there, the delivery system will take a while to catch up but it will catch up, and when you end up with a lot of guesses and wrong answers the scoring system will have a lot of reasons to tear you down.
The actual key relates back to my first point -
don't miss easy questions, especially early in the test. If you get 7 of the first 10 right, you're well on pace for a great score. You don't need to get all 10 - your right answers will mean that the delivery system is already throwing you very hard questions. The key is to not miss, for example, 7 of the first 10. If you do, the delivery system is showing you easier questions and you run the risk of running out of opportunities to "earn" and succeed on harder questions. Especially because you're human - you will make a dumb mistake on at least one problem you should get right. If you make those mistakes early, your margin for error is very thin later in the section. So the takeaway - be patient early (double check your work, don't stress the clock too much) and set yourself up for success. But DON'T kill yourself trying to get them all right. You won't.
3) Don't be afraid to guess / Learn to let goPeople often rush through "easy" questions to save time for harder questions, when the above advice really tells you to do the opposite. But obviously the clock will be factor. How do you save time to be patient on questions you should get right?
-Know when to let go of a question. If after a minute you just don't see a path to the finish line, it's ok to blindly guess. There's a great story that one of the "godfathers" of the GMAT told me once (he's seen/known as the main guy who oversees the test for GMAC). He was taking the test for R&D purposes and as a math PhD he really wanted a perfect score. One tough geometry question was giving him trouble and he spent maybe 6-7 minutes on it trying to get it right, laughing to himself that he knows it's horrifically stupid to spend that much time on any one question. As the main man at GMAC he was able to check the "back end" results the next day...when it turned out that that question was one of the unscored experimentals - it didn't even count! Even the guy in charge of the test has to guess sometimes; it's ok for you to do it, too.
-If you're going to struggle on time, it's better to blindly guess once or twice (to earn your 2-4 minutes back) than to rush to save 10-15 seconds on each question. Silly mistakes will really hurt your score, but since you *know* you'll get at least 7-8 questions wrong (*everyone* does) you might as well guess once or twice when a question just looks like it's not going anywhere. Take your 20% (or hopefully better if you can give it a quick educated shot) chance so that your must-haves are 100% chances and not 90.
4) Take practice tests so that you know what this all feels likeLike Hamid said above, there's no substitute for practice. If you've done several practice tests you can get a good internal clock going to let you know when you're moving too slowly or too quickly, and you can play around with certain milestones (if you've used 22 minutes after the first 10, do you still feel comfortable throughout?) to write down or keep in mind. There's no substitute for practice.