You know what else will filter out dumb people? A vague open ended problem that is relevant to the position you're hiring for. Have them write an abstraction la

You know what else will filter out dumb people? A vague open ended problem that is relevant to the position you're hiring for. Have them write an abstraction layer for two different implementations of [insert relevant problem here] or refactor messy duplicated code into reusable [methods/components/modules]... Better yet, find an actual problem that your engineers actually had to solve in the past and see how they do it.