A high reliability organization (HRO) is an organization that has succeeded in avoiding catastrophes in an environment where normal accidents can be expected due to risk factors and complexity.
Important case studies in HRO research include both studies of disasters (e.g., Three Mile Island nuclear incident, the Challenger Disaster and Columbia Disaster, the Bhopal chemical leak, the Tenerife air crash, the Mann Gulch forest fire, the Black Hawk friendly fire incident in Iraq) and HROs like the air traffic control system, naval aircraft carriers, and nuclear power operations.
History
HRO theory flowed out of normal accident theory, which led a group of researchers at the University of California, Berkeley (Todd LaPorte, Gene Rochlin, and Karlene Roberts) to study how organizations working with complex and hazardous systems operated error free. They researched three organizations: United States nuclear aircraft carriers (in partnership with Rear Admiral (ret.) Tom Mercer on the USS Carl Vinson), the Federal Aviation Administration's Air Traffic Control system (and commercial aviation more generally), and nuclear power operations (Pacific Gas and Electric's Diablo Canyon reactor).
The result of this initial work was the defining characteristics of HROs hold in common:
"Hypercomplexity" – extreme variety of components, systems, and levels. Tight coupling – reciprocal interdependence across many units and levels. Extreme hierarchical differentiation – multiple levels, each with its own elaborate control and regulating mechanisms. Large numbers of decision makers in complex communication networks – characterized by redundancy in control and information systems. Degree of accountability that does not exist in most organizations – substandard performance or deviations from standard procedures meet with severe adverse consequences. High frequency of immediate feedback about decisions. Compressed time factors – cycles of major activities are measured in seconds. More than one critical outcome that must happen simultaneously – simultaneity signifies both the complexity of operations as well as the inability to withdraw or modify operations decisions.
While many organizations display some of these characteristics, HROs display them all simultaneously.
Normal Accident and HRO theorists agreed that interactive complexity and tight coupling can, theoretically, lead to a system accident. However, they hold different opinions on whether those system accidents are inevitable or are manageable. Serious accidents in high risk, hazardous operations can be prevented through a combination of organizational design, culture, management, and human choice. Theorists of both schools place a lot of emphasis on human interaction with the system as either cause (Normal Accident Theory - NAT) or prevention (HRO) of a systems accident. High reliability organization theory and HROs are often contrasted against Charles Perrow's Normal Accident Theory (see Sagan for a comparison of HRO and NAT). NAT represents Perrow's attempt to translate his understanding of the disaster at Three Mile Island nuclear facility into a more general formulation of accidents and disasters. Perrow's 1984 book also included chapters on petrochemical plants, aviation accidents, naval accidents, "earth-based system" accidents (dam breaks, earthquakes), and "exotic" accidents (genetic engineering, military operations, and space flight). At Three Mile Island the technology was tightly coupled due to time-dependent processes, invariant sequences, and limited slack. The events that spread through this technology were invisible concatenations that were impossible to anticipate and cascaded in an interactively complex manner. Perrow hypothesized that regardless of the effectiveness of management and operations, accidents in systems that are characterized by tight coupling and interactive complexity will be normal or inevitable as they often cannot be foreseen or prevented. This pessimistic view, described by some theorists as unashamedly technologically deterministic, contrasts with the more optimistic view of HRO proponents, who argued that high-risk, high-hazard organizations can function safely despite the hazards of complex systems. Despite their differences, NAT and HRO theory share a focus on the social and organizational underpinnings of system safety and accident causation/prevention. As research continued, a body of knowledge emerged based on the studying of a variety of organizations. For example, a fire incident command system, Loma Linda Hospital's Pediatric Intensive Care Unit, and the California Independent System Operator were all studied as examples of HROs.