Another component to keep in mind with programs with poor pass rates (<90%) is to look at the make-up of their residents. From glancing at most of the programs that I've seen with poor pass rates, most of the programs had a large perecentage of FMG's (not trying to start a debate, just my observation), on top of possibly being a program in dissarray or with financial/social problems (a couple specific ones come to mind in LA), and in the end had to fill them with people less interested, qualified, or who simply had to scramble last minute.
In the end, it's up to the program to establish goals and help remediate problems such as poor pass rates, so I think looking at a pass rate from one year is less important than looking at how poor they've done over a longer period of time. Just my two cents.