What is the test for determining whether an administrative body or agency has quasijudicial power to extend privilege to an otherwise defamatory publication?

In determining whether an administrative body or agency possesses such quasijudicial power so as to extend the privilege to an otherwise defamatory publication, we consider whether the administrative body is vested with discretion after investigation and consideration of evidentiary facts, whether it is entitled to hold hearings and decide the issue and, more importantly, whether its power affects the personal or property rights of private persons. (Tiedemann v. Superior Court (1978) 83 Cal.App.3d 918, 925.) "[S]trong policy reasons exist to assure free and open channels of communication between citizens and public agencies and authorities charged with the responsibility of investigating wrongdoing [citation.]." (Ibid.)