Perhaps the argument that it isn't possible to assess merit for a job position is so far outside the realms of reason that asking for clarification is the only way to formulate an answer.

But if you want a simple, quotable answer for the obvious question as it is written, here you go:

• Asses the criteria for which a job would be considered to be successfully performed.
• Check if historical evidence/experience/current skill/expected future growth gives indication that the candidate could meet or exceed those criteria.
• Rank the candidates, based on how well they match to the success criteria.
• ???
• Profit?

It's tremendously disappointing to see people act like assessing fitness for a role isn't a thing that has been going on since the dawn of civilisation.

Get a grip.

Now, if you want argue that this isn't how things are currently done ? I’m right there with you.

The system is a shambolic remnant of what it should be ? couldn't agree more.

A lot of it is probably by design ? sure, i'm down for that perspective.

But "It isn't possible to assess merit for a job role", is a troll at best or extreme ignorance at worst.

If people weren't asking "are you sure that this is what you meant?" i'd be worried for the state of basic reasoning.