Ian Stewart wrote:

iamcste wrote: Hi Ian,

thanks for your great posts. Can you please elaborate on the overpenalize part? Is this true and how much can it impact you, can it really reduce your raw verbal points by more than 10 (meaning 40 to 30 because you mismanaged time)

The short answer is: I don't really know; only the test designers know precisely how the question selection algorithm works. I ca say the following with some confidence:

* It doesn't hurt you much to get an 800-level question wrong; that only proves you likely aren't an 800-level test taker. It hurst a lot more to get a 400-level question wrong;

* The description you read in prep books about the algorithm ('get a question right, your next question is harder; get a question wrong and your next question is easier') is an oversimplification. There are several factors that the algorithm uses to select your next question, and your ability estimate is only one of those factors (the test also needs to ensure content balance, and that no question is overused). So even if you are doing well, it is possible to see questions which are 'easy', and which still count, and these could show up at the end of your test. If you don't have time to attempt these, you're risking answering an easy question incorrectly.

* Some of my higher scoring students told me that they found the end of their test much easier than the beginning. Now, that may just be coincidence, but near the end of the test, the algorithm has a lot of information about your level; it is, perhaps, then less important to deliver questions near your ability. So while I have no way of knowing for sure, it strikes me as a possibility that there may be questions near the end which are of a lower difficulty than you might expect. Were I designing the test, and if I wanted to ensure that later questions were as important as early ones, that's something I would consider, at least. Whether the real test works that way I can't say - I only have anecdotal evidence to go on.

* Pacing of course is critical, but for your score to fall from a 40 to a 30, you would need to miss quite a few questions; answering one or two questions incorrectly at the end certainly will not make your score fall that far. If you needed to guess at 10 questions in a row at the end, however, then your score could fall quite dramatically.

GMATMadeEasy wrote:What is GMAT focus you mentioned there ?

My guide was the following template (literally): weak analogies, correlation vs causation, necessary versus sufficient, statistical problems such as bias, relevance and sample size, and things changing over time.