Why is exam 8 harder than it used to be?
If you look at the excel file with the passing stats on this page you will see that from 2000-2010 there was not a single sitting that had a passing rate that was in the vicinity of 30s. In fact, the weighted average of the pass percentages is 48.4% which was the highest of any upper.
Since 2011 pass ratios have routinely been in the 30s with exam 8 having the lowest weighted pass ratio. How did this exam go from being the easiest to being the hardest?
The advanced ratemaking exam was called Exam 9 in the pre-2011 syllabus, and was still administered in the Fall. Exams 8 and 9 were switched in number so that the fall exams were all even numbered and the spring exams were all odd numbered. This was also before exams 5 and 6 were offered twice a year.
Difficulty manifests in ways that may not show up in the pass ratios. There is a bulk adjustment downwards on the MQC for more difficult/defective or longer than expected exams which ends up bringing the pass ratio back up.
Perceived difficulty tends to increase any time the question types change. It happens when multiple choice was removed, when blooms was introduced, when IQs were introduced, transition to CBT, or when significant portions of the syllabus is revised, because prior exam questions are no longer as useful.