It's great to see some objective research being done on this, and I am very interested in following the results.
They mention evaluating the effectiveness of giving a candidate a project to do "in their own time." I recently had a interview that included this and I can share the result: I accepted an offer from a different company that didn't require it. I doubt my life is that different than anyone else's, with a full-time job and a full-time life outside of work. Spending that much time to qualify for a single job is too much to ask of anyone. If it were to pass a generic proficiency certification applicable to many positions, I would consider it, but this does not scale if a candidate is applying for multiple positions.
They mention evaluating the effectiveness of giving a candidate a project to do "in their own time." I recently had a interview that included this and I can share the result: I accepted an offer from a different company that didn't require it. I doubt my life is that different than anyone else's, with a full-time job and a full-time life outside of work. Spending that much time to qualify for a single job is too much to ask of anyone. If it were to pass a generic proficiency certification applicable to many positions, I would consider it, but this does not scale if a candidate is applying for multiple positions.