Paleontologists believe that fragments of a primate jawbone unearthed

Dear Ergenekon,
My friend, please forgive me if I misattributed certain motives or interpretations to you without cause. In your prior post, you said:
"We do not have any reason to believe that the gmat regards its guides as much as its real exam questions. Having mostly not clear explanations for og problems shows otherwise."
This is what lead me to believe you were critical of the OG explanations.

I was not aware that Stacey or Ron from MGMAT ever spoke badly about any official questions. Those are two seriously brilliant people for whom I have tremendous respect, and I have never heard them say anything negative about the questions.

Yes, the GMAT has evolved over the years, but many of the standards have remained the same. Some of the old questions might have been released years ago, but in many ways, they are still representative of the standards that the GMAT still maintains. All test questions, even older test questions, have been through a rigorous vetting process, so they are uniformly on a much higher level than almost all other test prep questions from other sources.

I don't know for sure, but my understanding is that the questions that make it into the OG are among the better questions that the GMAT chooses to retire. There is a tremendously long selection process, whereby questions are vetted and refined and entered into the active pool of live test questions. Every now and then, for exam security, they remove some questions from that pool, and I think they choose some of the better quality questions from among these for the OG. I think we have good reason to suspect that the overall selections of topics --- say, the kinds of grammatical issues in SC --- are more or less representative of the distribution in their live question pool. Certainly, that is the implicit claim of their products.

In my view, nothing about the quality of the questions suggests in the least that there is anything suspect about the products as a whole. I have met some of the people at GMAC, and I have been very impressed with their concern for presenting a rigorous and fair product. While their primary concern is for the live test itself, this concern also extends to all the products they offer. They are deeply concerned with maintaining a consistent high quality across brand.

I would urge you to find out a little more about this company and how it operates. I am not easily impressed, and I have been impressed by this company.

Mike