how do you qualify if someone is qualified? how do you know what percentage of these people is unqualified? do you go by the rate who is not hired? i know there

how do you qualify if someone is qualified? how do you know what percentage of these people is unqualified? do you go by the rate who is not hired? i know there's people out there applying for jobs they don't have the required skillset for, don't get me wrong. but these numbers which are posted say nothing about that, and so no observation can be made on that point? Or am i missing something further?