Although they may seem diverse, these organizations have a number of similarities. First, they operate in unforgiving social and political environments. Second, their technologies are risky and present the potential for error. Third, the severity and scale of possible consequences from errors or mistakes precludes learning through experimentation. Finally, these organizations all use complex processes to manage complex technologies and complex work to avoid failure. HROs share many properties with other high-performing organizations including highly trained-personnel, continuous training, effective reward systems, frequent process audits and continuous improvement efforts. Yet other properties such as an organization-wide sense of vulnerability, a widely distributed sense of responsibility and accountability for reliability, widespread concern about misperception, misconception and misunderstanding that is generalized across a wide set of tasks, operations, and assumptions, pessimism about possible failures, redundancy and a variety of checks and counter checks as a precaution against potential mistakes are more distinctive.