I have taken every test there is regarding both state licensing, which was the National Home Inspectors Exam, the ashi exam, the INACHI exam, and none of them would make an inspector a better inspector if the tests were passed in my opinion.
All of the questions are just a baseline (silly questions) so an individual or the testing institution (if proctored) knows the inspector just knows the basics of the profession, there are way too many circumstances in the field in which none of the testing makes any difference if a person passed or failed.
The circumstances the inspector finds at the inspection require way more knowledge than is on any test provided by any proctoring agency or association.
None of the testing I took has questions in which certain circumstances which each one of us come across daily are a question in the tests, which is the most important part of this profession, combining common sense with building construction knowledge.
As an example:
Different types of Flashing installations and how they relate to the performance of the building being one prime example of a circumstance in which if an inspector did not know how a house or commercial building should be constructed to keep water out of it none of the testing would be helpful, field experience is a must, combined with common sense, and what makes different types of material when applied in combination function if installed correctly, or why things fail if they are not installed correctly. Lot of common sense involved in this profession, combined with field experience, testing is silly.
Basically I think any proctored test is a waste of time and money.
The inspector better know everything there is to know about every system and component in a building which is required to be inspected by a standards of practice, if the inspector doesn’t, he will either be in court, or out of business.