The Delphi technique: Past, present, and future prospects — Introduction to the special issue

The Delphi technique has been around for over half a century, so now seems a proper time to consider its past, present and future. This introduction characterises the papers in this special Delphi issue, which include both conceptual and empirical works. It summarises the main lessons that have been learned from these for the conduct of the technique, and provides a call for more and better empirical studies in the future.