I don't know that you'll find any real statistics on this, though it actually might make for an interesting study. I think that Qbank is best viewed as a learning tool rather than a prognosticator of your real-world performance. Go through the entire thing, and take the time to review topics that you're a bit rusty on.
That being said, from personal experience and that of my friends, a consistent 60-65% on Qbank is an excellent indication that you will pass Step II. I'd say that a consistent 75% (with no cheating!) will likely place you within the upper quartile if you're not someone who freaks out when it comes to the real thing.
Hi friends!!! Is there much of a difference between the 2000-2001 edition kaplan books & the 2004-2005 edition ??? I am strapped for cash & the older edition seems cheaper so, some one who knows the difference please, answer me.