 Even though far more people die than require new organs, organs are scarce. Numerous factors affect the retrieval of organs from the dead. These include: the nature of people’s deaths (in only perhaps fewer than 1% of deaths can organs currently be taken, and countries vary according to the number of strokes, car crashes, shootings, and other causes of death that lend themselves to retrieval); the number of intensive care units (ICUs) (most donors die there and fewer ICUs makes for fewer donors); the medical factors that determine whether organs are retrieved successfully; the logistical factors that determine the efficient use of available organs; the extent of public awareness of transplantation; and the ethical-legal rules for consent that determine who is allowed to block or permit retrieval. Although most of these factors do not raise philosophical questions, it is important to realize that the main factor that does—the ethical-legal system for consent—is only one of many that affect retrieval rates, and nowhere near the most important at that. One should also bear in mind that the variety of factors plus unreliability or incomparability in statistics about retrieval mean that it is hard or impossible to have confidence in many of the causal claims about how consent rules affect retrieval rates.