This is why we at Lytmus believe the most effective way to assess a candidate is to see how they perform on a real work sample. We've built up a virtual machine based platform that allows candidates to showcase their skills in a real development environment with working code cases (web, mobile, data, systems, etc.). Most interviewing methods like algorithmic challenges often only provide signal into a discrete skill that can be acquired through practice, whereas what matters is whether or not you can actually work on real world projects, understand an existing code base and perform on the job as opposed to on an interview coding challenge. Google's SVP of People Ops Laszlo Bock also writes about the ineffectiveness of indirect tests and their weak correlation with on the job performance.