Organizational encounters with risk and error are not restricted to the sensational cases that draw media coverage when mistakes, near misses and accidents become public. They are, instead, a routine and systematic part of daily organizational life that only occasionally become visible to outsiders.

Merton was the first to observe that any system of action can generate unexpected consequences that are in contradiction to its goals and objectives (1936, 1940, 1968). Recent research affirms his observation: unanticipated events that deviate from organizational expectations are so typical that they are ‘routine non-conformity’ – a regular by-product of the characteristics of the system itself (Vaughan 1999). The public learns about only the most egregious of these. Because routine non-conformity is a regular system consequence, complex organizations that use or produce risky technologies may have encounters with risk daily.

In this chapter, I compare daily encounters with risk for two organizations for which mistakes result in public failures and have high costs: the Federal Aviation Administration's National Air Transportation System (NATS) and the National Aeronautics and Space Administration's (NASA) Space Shuttle Program (SSP). My logic for comparing these two agencies is grounded in two related strands of research. Barry Turner investigated the causes of eighty-five different ‘man-made disasters’. He found an alarming pattern: after a disaster, investigators typically found a history of early-warning signs that were misinterpreted or ignored. A problem that seemed well structured in retrospect was ill structured at the time decisions were being made (Turner 1978; Turner and Pidgeon 1997).