Are case studies the new thing?

For 2 jobs i recently applied to in the high tech/start up industry, they gave me case studies they wanted me to do. They gave me a few days to a week to do them. One i was able to do relatively easy but the other literally would of taken me 40 hours to do. Are a lot of companies using case studies to weed out applicants that can at least past the initial phone call interview?

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