The strongest signal is just identifying whether they've built something before. You can find that in various different ways: * Do they have original work publ

The strongest signal is just identifying whether they've built something before. You can find that in various different ways: * Do they have original work publicly available? (Github, Gitlab, ...) * In the interview can they talk in more than surface detail about past work/projects. * Do they have a blog where they talk about what they've learned over their career? Hiring is always going to be a risk but looking for ways to see or get them talking about what they've built and what they learned while doing it is the most effective signal I've found as to whether they can do the job.