I stumbled across a blog post on Hacker News outlining why even short, bullshit programming excercies are poor proxies for actual job performance.
But the choice bit was found in the comments:
For a few days! You’re assuming employers have the luxury of that kind of time? We don’t. You are one of (at least) dozens of applicants Recruiting has to deal with in any given month. Expecting us to assign an employee to work with every potential hire for multiple days is disingenuous. <footer>— BUF</footer>
And there it is. There’s your problem.
Don’t have applicants.
Focus on one possible hire at a time - one you hand-select and go hunt for. And then spend as much time as you need to make sure they can do the job, you can work with them and they’re going to be happy working with you.
That’s it. That’s the book I’m writing.
Hiring is the most important thing you do as a company.
Stop half-assing it.