Matt Mullenweg of Automattic has a practice where he interviews all new hires, at first, through live chat.
Jason Fried of Basecamp puts written communication skills central to his hiring process. All designers have to do a test design project and then write up and explanation of why they designed it how they did it.
In companies of programmers and designers, you would think they would look for the best designers or programming skills... but that is not the case.
They look for the best writers and communicators.
At some point, the skills of an individual don't matter if you struggle to communicate with them.
A great designer is no good if they have an ego and can't communicate properly with the team.
In today's age of Slack, email, and project management tools, so much of our work is done online.
So when you are looking for new candidates for your company, test their writing.
Email back and forth a few times before hopping on an interview.
Consider holding your first interview over a live chat.
It's different, but in most remote companies, you will spend more time writing with this person than speaking directly.