First, a chart:
As a wise man once said, "That's fucking interesting. That's fucking interesting, man."
The chart seems to make sense — for candidates starting in 2013, they might pass one section and then fail and fail and fail and fail and then the 18-month window hits some time in 2014 and he or she thinks, "Well, this isn't for me," and they go on their merry way.
It's a little more painful for someone who started the process in 2012. He or she might have some early success, passing a section or two, thinking they are on cruise control to passing the rest of the sections and then some combination of life, work, and failure after miserable failure dissuades this candidate from passing his or her remaining sections. This person looks at the situation and probably concludes that killing themselves for the credential isn't worth it. That has to be pretty gut-wrenching. Or liberating!
Anyway. What isn't clear, and I won't do any wild speculating at this point, is if the drop-out numbers are trending in a way that further supports what we've been hearing from the AICPA
: that although more people are going into accounting, fewer are sitting for the CPA exam (or, in the case of drop-outs, saying, "Ah, fuck it.").
I've emailed NASBA to see they have some data that can put the above numbers in context. In the mean time, there's nothing to stop you all from discussing these numbers and what they might mean.