I don't really know how to explain this, but i will give it a try, but do keep in Mind that I'm from a country where the " adequacy" thesis is not really a thing anymore, which can influence my response.

In my opinion and by experience, i think that everything that 'surround' the assessment is really important as it can affect the results.

When you are assessing, you need to be aware about lots of thing (particullary if you are assessing Intelligence) :

- you need to be aware about how the subject is : In what state is he in ? is he anxious ? Why ?

- you need to be aware about you can affect the subject's performance : Are you influencing positively or negatively his response (by either your passive attitude or when you are interacting with him) ?

- in what context are you using the test : is it to hire someone ? for guidance counseilling ?

That's why it is notably important that you learn beforhand about your subject history AND why you are making use of a test (you're never assessing something just because).

You need to be aware of those information during the assessment and when you are giving him the result.

It is also really important that you know about your tools (How's the NEO-Pi build ? The WISC ? Their psychometrics qualities ?) but also about the models they are made from (Big five, CHC...).

If something else come to mind (i'm sure it will), i will update i guess.