A lot goes into it but the most important two things are:
1. Study Skills and
2. Study Time
“Is it possible to study as much as you can and not pass ever?”
Yes it's definitely possible. It is not how MUCH you study, it is about how well you study. Big difference.
“So, your not intelligent enough?”
Sure having lower intelligence can hurt your chances – but if you have a degree, your probably smart enough – you just may need to have more study time and/or better study skills than others who are smarter than you.
“I think there are a lot of other factors, such as luck.”
Luck has VERY little to do with it IMO.
“There is also test anxiety.”
Agreed. Test anxiety and time management can have big impacts – although these are things, if you recognize, you can overcome.
“I wouldn't go as far as to say that anyone can pass these tests.”
Agreed. Although, I think that under perfect conditions (say – take a year off, treat it like grad school, get a great review course, and study) and with good time management and good study skills, most everybody would be able to pass. It's just that people are working, aren't good studiers, don't have enough time to study…etc. that throws people off. No one has perfect conditions but it is important, more important for some, to have better conditions than others.
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