If you can, in your hiring process, get a decent prediction of effectiveness and competence, and stipulating that passion does not connote effectiveness and competence, is it smart to screen for passion?
Yes, I think it is. Given two candidates of equal competence, I'd naturally prefer the one with the greater passion for the particular kind of work the job would entail. Does that really seem strange?
Of course it gets trickier when the more competent one seems the less passionate. Then it's a question of how much to weight the two dimensions (along with whatever others one is considering). I have no magic formula here; I think it depends on the circumstances.
There seems to be a subtext here that work sample tests give no indication of passion. I don't think that's true; when I've given people programming exercises, I think the craftsmanship of the code (is it well-modularized, well-documented, nicely indented, etc.) is indicative of their passion. Competence, to me, is more about whether the code works.
So yes, I'm using craftsmanship as a proxy for passion, so I suppose next you'll ask, why not just go for craftsmanship? The point we seem to be coming to is that passion is difficult or impossible to measure directly, so why not stick to qualities that are more measurable?
I don't think everything important is easy to measure.
I'm just feeling we are using the words in different ways. I'm not a native English speaker but for me effectiveness is a term that includes passion. You can be competent in your work but effective at deflecting it (it's painful to work with such people), I believe that if you are passionate about doing the work it will also mean your effectiveness is in the right direction.