[jollybean]

It's impossible to gather someone's competence from a resume or even in a conversation.

A 4hr assignment is generally a really good way to gather competency.

That said - it's just 'too much' of a hill for senior devs. to bother with and there are probably some ways to do 'regular interviewing' in order to figure that out.

I have hired a ton of Engineers and I've found a lot of senior engineers to be particular, crusty and a bit weird: excelling in some ares, but cantankerous in other ways.

But yes, 4hr hr take home is going to be a barrier.