Is my education valid?

As some of you know, I recently started a new job. I am not going to elaborate on that any further on this blog, so, don't ask.

However, I am going to share some thoughts and discoveries.

First the positives.

1) I have had and will get more training in my current job in the first year than I ever got in my 5 plus years in my previous job.

2) That the emphasis on catering to the LEARNING NEEDS of the students are a focus is a HUGE advance in the education system in Singapore that I never expected.

and lastly

3) Understanding that knowledge (book or paper smart) without skill doesn't improve employability, even though late, is GREAT.

I am not going to state the negatives. Well, I am going to try not to. But I have one major point to bring up and it has to deal with the title of this post.

In my 2 and a half weeks (13 days) of hire, I have had to attend almost 10 days of classes. Some of the classes repeat different theories (kind of a reinforcement tool, I think). 3 of the classes have portions (or the entire class) dedicated to assessment theories, methods and tools. 

And the thing I keep hearing is:

When you are using a test (like a quiz or exam that contains multiple choice questions or short answer questions or even essays) as an assessment tool, you have to always check for the "validity of the assessment against the learning". 

It keeps being stressed upon as if it is a new idea... which leads me to wonder if previously, tests were set and had no validity to the learning.

I can't imagine otherwise. If not, why would this topic be brought up so many times. 

As far as I can remember, in my previous profession as a corporate trainer, the only way you could ask a test question, is if you had mentioned it in the material. Or, in the case of some trainers who did not help set the test questions, they taught the material toward the answers to the test questions. The test questions ALWAYS remained valid to the material and that's the only way I can see it. Why the revelation? And the stress on "validity"?

Did our tests, when I was in school, not have "validity", therefore, it is invalid, therefore, my education was invalid?