This is the official statement of the CFAI. Does anybody know how this is calculated? My guess would be first exam date to last, meaning five exams on average, or does it include perpetration time for the first exam.
On the same page of the CFAI website they also post that you should take into account roughly 6 months of studying per exam. So I believe it includes preparation. Also, there is of course survivorship-bias in this statistic, as it only includes the people that actually passed all three levels and doesn’t include all the people that didn’t. Hope this helps! 🙂