INTRODUCTION
What drives the decision to become a potential organ donor? Since 1995 over 45,000 people in the United States have died waiting for a suitable donor organ. Although an oft-cited poll (The Gallup Organization, Inc., 1993) has shown that 85% of Americans approve of organ donation, less than half had made a decision about donating, and fewer still (28%) had granted permission by signing a donor card. Given the shortage of donors, the gap between approval and action is a matter of life and death. To learn more about what causes people to become donors, looking at differing organ donation rates between countries might provide a clue. Even across neighbor states, organ donation rates vary widely. Within the European Union, for example, donation rates vary by nearly an order of magnitude across countries, and these differences are stable from year to year. Factors such as transplant infrastructure, economic and educational status, and religion all explain part of the difference (Gimbel, Strosberg, Lehrman, Gefenas, & Taft, 2003). However, even when these variables are controlled for, large differences in donation rates persist. Why?
Most public policy choices have a no-action default, that is, an assignment to a condition that is imposed when an individual fails to make a decision (Camerer, Issacharoff, Loewenstein, O'Donoghue, & Rabin, 2003; Sunstein & Thaler, 2003). For example, in the case of organ donation, European countries have one of two default policies.