I can always tell (multiple passes/failures to back it up – unfortunately) and am definitely not kidding myself. I typically practice both the 2015 & 2016 AICPA released moderate and difficult questions before each exam and will mentally compare the formats to my testlets during the exam (don't do this, I have a problem and don't be like me).
You should have access to these if you buy the Ninja MCQ for whatever applicable section. Of course subjectivity does come into play – as in a question won't seem difficult to you if you have studied the content in that specific area hard enough. I typically find that it doesn't have to do with the wordiness, or calculation dependency in a question but more obscurity/ two questions could be correct. Or the general wording could be annoying.
But to echo what everyone else will say, you shouldn't waste time on the exam trying to assess if you think it is moderate or difficult, you should just focus on answering the question (I clearly don't follow this advice lol). At the end of the day all that matters is you study and prepare as best you can – and try and nail the SIMs of course!
General caveat though – if you are scoring in the high 80's/90's on the exam, it would probably be more difficult to assess the difficulty. This is because that is such a master level of understanding of the material you are literally crushing every question on that exam and destroying anything in your path so it probably all seems pretty easy! For someone like me on the other hand, who is providing uh, “reasonable” assurance to the test makers that I know my stuff…well it's a bit easier to assess.
FAR - 76 - [4]
BEC - 71, 73, September 9 2016
AUD - July 28 2016
REG - October 2016
Black coffee, stress, and cottage cheese pancakes!