Dear Reed,

The ranking of a school's MBA program has no real correlation to the quality of its PhD program. There are definitely some schools that have both strong PhD and MBA programs, but I would not use the MBA reputation as an indication of the PhD. With regards to the GMAT score, it is hard to say as PhD programs do not always release the same statistics. Generally speaking, PhD admissions tend to weight transcripts and standardized test scores heavier than work experience but also scrutinize why you want to study your discipline and what your research interests are. Most faculty (not all, but most) tend to want PhD students with interests similar to their's, so if you know there are senior faculty at the school with similar interests to yours then you will be more attractive to that program.

US News & World Report does a PhD ranking each year and you might find it useful for information. The best way to tell the strength of a PhD program is look at where the recent PhD graduates placed--are they offered jobs at top tier undergraduate universities? second tier? If you do not want to teach/research at a university, then this might not be as important to you. If you want to work post-PhD, then you can evaluate industry placements to see if the school has ties to the industry you want to be in upon graduation.

That's about all I know on the PhD front. Best of luck to you!
Lisa