[hyperzeit]

To me, this alone could also be a collider/Berkson's paradox: Conditioning on making the cut, there is a negative correlation because you make the cut by either being extremely skillful or by having great certifications – one compensates the other. That in turn would mean that certifications are actually positively correlated with getting employed at Google.

You need the full picture, that is people not making the cut to exclude this pattern.