Johnson and Goldstein first proposed that switching from an opt-in to an opt-out system for deceased organ donation-where all eligible individuals are presumed donors unless they opt out-could save many lives. Countries using opt-out policies were reported to have up to six times higher registration rates for deceased donation 1.

Encouraged by these findings, several nations have adopted opt-out systems, including England and the Netherlands 2. However, earlier evidence from Belgium suggested that presumed consent may negatively impact living kidney donation3. A recent cross-country analysis has confirmed this concern. Güntürkün et al. reported that while opt-out policies led to a small, statistically insignificant rise in deceased donors (+7%, +1.21 per million population), it caused a significant decline in living donors (−29%, −4.59 per million population)4. The study concludes that opt-out defaults may produce crowding-out effects, as people perceive organ shortages to be solved, reducing motivation for living altruistic donation.

The infographic summarises these findings, emphasising that while opt-out systems may appear beneficial, they can inadvertently reduce overall organ availability by discouraging living donors.

References

1. Johnson EJ, Goldstein D. Do defaults save lives? Science. 2003;302(5649):1338–9.

2. Jansen NE, Williment C, Haase-Kromwijk BJJM, Gardiner D. Changing to an opt-out system for organ donation—reflections from England and the Netherlands. Transpl Int. 2022;35:10466.

3. Looze KD, Shroff S. Can presumed consent overcome organ shortage in India? Lessons from the Belgian experience. Natl Med J India. 2012;25(3):168–71.

4. Güntürkün P, Studte S, Winkler D, Clement M, Tan JHW, Merz E-M, Huis in 't Veld E, Ferguson E. Crowding-out effects of opt-out defaults: Evidence from organ donation policies. PNAS Nexus. 2025;4(10):pgaf311.