You're fortunate in that your employer only requires you to do the easy and fun part of the job. I would therefore guess that you leave the engineering, which is mostly documentation, to someone else.
No, I do not leave engineering to someone else, PLEASE tell me what gave you that idea. Your "request for proof" is not 'engineering' but 'science'. However I am fortunate enough that all I have to make is what I call "documentation templates" for someine else to make 'pretty' documents from.

That's anecdotal evidence, perhaps, but in no sense is it proof
if 1 million people get sick from eating "Acme" and the factory removes the pigs feet extract from the product and from the on nobody get sick, what would you consider that? "anecdotal evidence"?.
Of course, the factory could feed concentrated pigs feet extract to some to see what happened, but I guess they would have some trouble to find volunteers.

In nuclear physics the scientist form a theory and then if it happens as he theorized, that IS considered proof.

It's just like your case where the phone calls stopped. stop harping on that one, I expanded on that in a previous post.

Erik