We don't really have an answer to that question. It is nevertheless a good one. What other studies have suggested—and not shown, in my view—is that, redacting information from job applications makes it more difficult to assess the extent or breadth of the experience in question, qualitatively speaking.
That is all the more important in the public service, given that managers have to be sure the applicant meets the merit criteria in order for that person to be screened in to the process. That's harder to do when a significant amount of information is missing.