[jurjenh]

I suspect the "being smart" is in terms that the employer can relate to - do they think about things in the kind of depth that I like / appreciate / can work with.

From my personal experience, I've dealt with smart people and smart people - one kind knows / understands a lot of things in a broad field, the other kind knows a lot about things but is almost completely devoid of common sense. I'd prefer the first kind in any situation where I or my friends would have to deal with them over the medium to long term. I'm pretty sure this would be reflected in all areas worth measuring for a company too.

So trying to define smart as a concrete measure may be missing the point, as you will actually have to work with the person, and what you feel is what tends to form your opinion / bias and affects your future interaction in such a way that it generally tends to become a self-fulfilling prophecy.