>If we though that unfiltered candidates were broadly similar then "hire at random, dismiss after N months based on performance" would be a great criteria, but I don't think anyone who has done much interviewing thinks that would be remotely viable.

I know a fair number of companies that do essentially that. They hire contractors for 6 months, at the end of 6 months the good ones are offered a full time position. The contractor company probably does some form of interview, but they are more interested in their 6 months of overhead from the contractor than quality candidates.

> since bad candidates interview more due to leaving jobs more often and taking longer to get hired

But there are also great people who interview badly.