I think interviews and code challenges have to be be decentralized and unscientific. Assessing likelihood of success in a software engineering role is genuinely

I think interviews and code challenges have to be be decentralized and unscientific. Assessing likelihood of success in a software engineering role is genuinely difficult; any single well-known credentialing program is going to generate experiences of its graduates being incompetent in the wild. And then no one will trust it anymore. People's own interviewing styles aren't any more valid, of course, but they operate at small enough scale to escape the kind of scrutiny that a standardized test would attract. People also don't like to admit they're wrong, and might be applying a kind of halo effect to colleagues who have passed their personal interview questions. Whereas people love to dunk on prestige, and will eagerly seize on anything they can count against someone with a prestigious credential.