Quant section queries: OG vs GMATprep vs Manhattan

Dear takasar12,

I'm happy to respond.

My friend, I believe one of two things, or perhaps both, might be going on here.

Scenario #1: GMAC, the folks who give the GMAT, have a truly enormous bank of high-quality questions and this bank spans the entire spectrum of the Bell Curve, from the absolute easiest to the absolute hardest. Eventually, those questions get retired. At this point, GMAC selects some retired question for the OG, but think about it. The purpose of the OG is to satisfy the needs of a general readership, the folks in the hump in the middle of the Bell Curve. Only a small percentage of the population would see either the easiest questions or the hardest questions, so those are not selected for the OG. Thus, the hardest questions on the GMAT would not show up in the OG, and a mathematically talented student taking the GMAT would see harder questions than those in the OG.
BTW, at some point, GMAC may decide to publish something such as an "Advanced Quant" guide, which would include some of those harder questions, but in the meanwhile, MGMAT and Magoosh can give you all the advanced math practice you need.

Scenario #1 would explain the difference with no change in the GMAT itself.

Scenario #2: It's also at least conceivable that the GMAT has been changing over time. Think about it. Say thirty years ago, it was mostly Americans that took the GMAT, my fellow Americans with their stereotypical strengths and weaknesses. Stereotypically, Americans of course are native English speakers, which confers a certain advantage on Verbal, and on average, Americans are not the sharpest at math. At this point, a large number of students from other countries take the GMAT, and not surprisingly, the two biggest contributor countries are the two large companies on Earth, China and India. Thus, compared to the past more Chinese-national and Indian-national students sit for the GMAT. Very stereotypically, students from China & India, on average, tend to be much stronger than Americans in terms of mathematical ability but tend to struggle on the Verbal side. Thus, if large numbers of these students are entering the test pool, over time, in order to maintain the same percentile values each year, the math would have to get a little harder and the verbal would have to get a little easier. Unlike scenario #1, this 100% speculation on my part. I can't tell you that it definitely is true, nor can I say what the time would be.
I don't know what the typical "life cycle" of an official GMAT question is--let's say, by the time it is released, it has served 10-15 years on the test. I have no idea whether that number is true. Then, a question released in 2005 was added to the pool, say, in the early 1990s, when the proportions of Chinese & Indian students taking the test were considerably smaller. If we account for the time lag between a question entering the GMAT pool and the same question being retired, then it may well be that the questions released 10-ish years ago were designed for the world 20-30 years ago--a very different world!
Again, all this is 100% speculation.

I hope this is helpful.
Mike

Makes plenty of sense Mike, was kind of speculating along similar lines. Thanks again. I'll go prowl the forums and try and find the general consensus.