The authors ran a large scale field experiment in Austria to tested the varying effectiveness of normative messages in letters sent to potential evaders of TV license-fees. There were three treatment conditions: (1) Threat: “If you do not respond to this letter, we will contact you personally”, (2) Moral Appeal: “Those who do not conscientiously register their not only violate the law, but also harm all honest households. Hence, registering is also a matter of fairness” and (3) Social normative appeal: “Do you actually know that almost all citizens comply with this legal duty? In fact, 94 percent have registered.”The mailings in general proved effective at raising compliance with the ‘threat’ treatment being the most effective. In this context social normative messages and moral suasion proved ineffective at changing behavior.