HR views recruiting as a funnel process, similar to sales. There are a set of screening steps testing different skills, and at each step you lose a fraction of candidates, until you get down to the set who accept offers.

E.g. https://www.jobvite.com/recruiting-process/7-benchmark-metri... https://www.glassdoor.com/employers/blog/4-tips-for-hiring-t...

That's a reasonable model, but it works best if all your filtering steps are effective tests for the things you care about. Getting that right is demonstrably hard, between some hiring managers who don't know or don't communicate what they're looking for, some recruiters who don't understand what they're looking for or how to recognize it, and some job-seekers who don't communicate or demonstrate their skills through the hiring process. And so everyone sees and resents flaws in the funnel.

I would love to read one from HR's perspective! Post if you see one.