I received an interesting email a week or two ago, and thought that I should share it with everybody, since I regularly receive similar questions:
I took the GMAT this week and scored 640 (Q44, V33).
I did about 3 or 4 practice tests, one from the downloadable MBA.com, and others from old editions of Kaplan and Princeton. I spent about $0 on prep (they were old CD's and books from my friend) and about 1 week's worth of time studying.
After reading your blog, somehow I'm dying to know...IF I were to work hard at it, do you think it be possible for me to reach, say 750 within a year?
This email came from a (very polite!) complete stranger who is nowhere near NYC. So without knowing anything else about her, I gave her a completely honest answer. In her case, I think it's fair to say that she has some quantitative talent, since she got a 44 on the GMAT quant without much effort. I'm pretty convinced that she'd be able to raise her GMAT quantitative score into the high 40s, and nearly anybody who works hard enough can pull his or her verbal score up by at least a few points. A 700 would be a reasonable goal for her, and it might not be crazy to think that she could achieve that without the help of a GMAT tutor.
Beyond that? A 750? I have absolutely no idea. I would have to spend at least a few hours tutoring her before figuring out how high she could go.
Here's the way I see it: almost any fluent speaker of English is capable of getting a 650, unless they have some extenuating circumstances such as learning disabilities or debilitating test anxiety (both of which are far more common than most people think--I have all sorts of thoughts about both, and might share them on this blog at some point). I'm not saying that it's easy to get a 650 on the GMAT. I'm just saying that a truly, deeply dedicated student could work like a lunatic and--on her best day--get a 650. I've seen plenty of people start at a very low level (say, 380-420) and ultimately crack 600. For them, 650 is doable.
After that? No guarantees, at all. It isn't fair, but I would argue that you need to have some sort of particular talent for "the GMAT way of thinking" if you want to crack 650. This "talent" might not be correlated to other forms of intelligence. You could be absolutely brilliant, and never have any shot at beating a 650 on the GMAT. Sorry, but that's just reality. Once you get beyond 650-level questions, you have to have a knack for "seeing" something in the question, or "making a connection" in ways that can't always be taught easily. A good GMAT tutor can increase the odds that you'll get the tough questions right, but some people really, really struggle to make much headway on those.
(Random example of a GMAT "hard gainer": one of my all-time favorite students started with a 420. She worked hard, but was bizarrely erratic with her GMAT practice tests, scoring everywhere from 380 to 540. On the real test, she stunned us both by scoring a 570, and got into her first-choice MBA program with a fourth-round application. She has zero GMAT talent, but she has been wildly successful in business school, and I swear that she will be CEO of something huge someday. She's intelligent, motivated, and awesome, and will be an outstanding business leader. Screw the GMAT, right?)
So whenever somebody contacts me--from NYC or from afar--and says that their goal is a 700 or a 750, and that they'll do anything to achieve that goal... I always try to tell them to chill the f*** out, as politely as I can. For some people, a 750 or a 780 is doable with a year's worth of studying. For others, a 700 is possible with a herculean effort. And for some, 650 would take a crapload of studying. It isn't fair, but it's reality. After a few hours of tutoring, I usually have a good idea of which category a GMAT student falls into, but it's awfully tough to tell from an email or a phone call.
One more thing I can tell you without knowing much about you: your work (and other) experience is far more important than the GMAT in the admissions process. If you're an amazing candidate with an amazing work ethic, the GMAT will be an irritation, but never an obstacle.