You can search petersons.com and most OT masters programs have acceptance percentages listed. They seem to be updated yearly. I've been surprised at how many applicants certain top OT schools accept... however, it raised the question of whether the schools really aren't that selective, or if most applicants to the top schools are really well-qualified. Accepting 60% of the general applicant pool is much less selective than accepting 60% of the cream of the crop OT applicants.
Regarding Board pass rates... I actually wrote a post yesterday and then didn't post it, because it opens a whole can of worms. Someone said that they were avoiding a certain school because they were concerned by the low pass rate. This does beg the question... is the low pass rate a reflection of a low-quality program which isn't teaching what students need in order to be successful on the exam? Or, is it a reflection of the relatively low-quality students? I know that's not a very PC thing to say, but it could be the case. Once upon a time, I went to law school. I attended an "elite" liberal arts college for undergrad, but went to my state law school because it was much less expensive than the other private laws schools to which I was accepted, even taking into consideration merit scholarships I was offered elsewhere. The school accepted a little less than 50% of applicants - a high acceptance rate in the world of law schools. Many of my fellow students were, quite frankly, pretty stupid. But, the program was excellent, and the exams were more rigorous than those taken by my then-boyfriend at a top 10 law school.
Some low-ranked law schools accept 80% of applicants! But these programs are weeder-programs. They give students a second chance, but don't dumb down the material. They lose a lot of students who flunk out, and some of those who make it through can't pass the bar exam. Of course one can question whether it's ethical to accept students who in all likelihood will never go on to be lawyers. But, the way I see it, they're giving second chances to people who made mistakes in the past, or had difficult backgrounds and had to cobble together undergraduate degrees from several different unprestigious colleges. And, they kick out students who don't meet a minimum GPA, so it's not like they string them along, just taking their money.
Anyway, my point is, obviously, like applicants to any other program, not all OT applicants are the same. They do not all have the same abilities. Are some of these programs with low pass rates merely accepting lower quality students who, despite a strong program, cannot pass the exam? If a program is accredited, I would say yes. So, that means that if you are a motivated and intelligent person, you're likely to be one of the 50% who DO pass. Now, this might also mean that your fellow students are not of the same quality as those at schools with higher pass rates, and that might matter to you. But I don't know if a low pass rate for a given school would automatically scare me off and make me think I would be unable to pass the exam.