The Pass rate for the CPJE from October 2013 - March 2014 was 74% ! This break downs for California schools it was 81.3% and Other US schools was 72.5%. (I got these numbers from CABOP website) Overall the exam isn't necessarily harder its just the NAPLEX is originally 185 questions and they throw out 35 of those you only need like 60% of the questions right so you can miss almost 80 questions and still pass the NAPLEX, yes I know its weighted but essentially you can miss a whole lot. Score range 75-150.
The CPJE is only out of 90 questions and they throw out 15, so even with the "hard exam" "easy exam" curve, you still can only miss like 18 questions and pass. Score range 75-99.
So the odds of passing are greatly in your favor for the NAPLEX and less so for the CPJE. Also I felt the NAPLEX was much more tough and the CPJE is much more straight forward. I think what happens is people are caught off guard with a LAW exam being 70-80%% therapeutics (50% is like retail stuff, how supplied patient counseling tips) 10% hospital stuff (safety goals, IV compatibility etc) and only like 10-20% LAW. I think that is what contributes to the low passing rate. The law exam pass rate in other states is almost comparable to the NAPLEX which the NAPLEX is 95% and most law exams being 90-95% passing rate. The wide range of variability of questions and the much more narrow passing score index is why its harder.