[skipping several caveats and simplifying assumptions]
Now, when you get those 200 resumes, and hire the best person from the top 200, does that mean you’re hiring the top 0.5%?
“Maybe.”
No. You’re not. Think about what happens to the other 199 that you didn’t hire.
They go look for another job.
That means, in this horribly simplified universe, that the entire world could consist of 1,000,000 programmers, of whom the worst 199 keep applying for every job and never getting them, but the best 999,801 always get jobs as soon as they apply for one. So every time a job is listed the 199 losers apply, as usual, and one guy from the pool of 999,801 applies, and he gets the job, of course, because he’s the best, and now, in this contrived example, every employer thinks they’re getting the top 0.5% when they’re actually getting the top 99.9801%.
Yup. Many programmer applicants famously couldn’t solve FizzBuzz. Which is probably because:
But such people are very obvious. You just give them a FizzBuzz test! This is why we have interviews, and work-trials.