 In addition, a scheme must take account of procedural values such as transparency, non-arbitrariness, and public deliberation (Miller 1999, ch.5). For instance, we may think that time spent waiting on a list is only a rough proxy for fairness. Perhaps someone entered a list late because of the difficulties in finding the time and resources to complete the requirements for listing; in perfect fairness that person should not be disadvantaged as a result. And yet time waiting is a visible and checkable criterion, whereas taking account of diverse social and economic circumstances would be procedurally fraught when it comes to ordering a priority list.