Sociotechnical systems

Starr, C., 1971, Benefit-Cost Studies in Sociotechnical Systems, in Perspectives on Benefit-Risk Decision Making, National Academy of Engineering p 17. 

The sociotechnical systems perspective is essentially top-down, in that it addresses the question of how the implications of management policies at all levels in the organization will affect the likelihood of errors with significant consequences. The sociotechnical systems perspective is therefore concerned with the implications of management and policy on system safety, quality, and productivity. 

The UK Health Safety Executive Research Program on Sociotechnical Systems... 

Many prescriptive models of organizational design exist (e.g., Hackman 1990), but relatively few studies applied specifically to test and inspection. Early work by Jamieson (1966), Thomas and Seaborne (1961), and McKenzie (1958) established that humans change their inspection behavior, and hence performance, in predictable ways when social and oiganizational variables are changed. Inspection, McKenzie notes, is always of people. The inspector is always judging the work of others, or even his or her own work. Thus, pressures on the inspector are to be expected. More recent work (e.g., Taylor 1991) has examined the sociotechnical systems context of inspection in aviation main-... 

Paradigm changes necessarily start with questioning the basic assumptions underlying what we do today. Many beliefs about safety and why accidents occur have been widely accepted without question. This chapter examines and questions some of the most important assumptions about the cause of accidents and how to prevent them that just ain t so. There is, of course, some truth in each of these assumptions, and many were true for the systems of the past. The real question is whether they still fit today s complex sociotechnical systems and what new assumptions need to be substituted or added. 

New Assumption 2 Accidents are complex processes involving the entire sociotechnical system. Traditional event-chain models cannot describe this process adequately. 

In the traditional causality models, accidents are considered to be caused by chains of failure events, each failure directly causing the next one in the chain. Part I explained why these simple models are no longer adequate for the more complex sociotechnical systems we are attempting to build today. The definition of accident causation needs to be expanded beyond failure events so that it includes component interaction accidents and indirect or systemic causal mechanisms. 

The reason for this discussion is to explain why the definition of the hazards associated with a system is an arbitrary but important step in assuring system safety and why a system engineering effort that considers the larger sociotechnical system is necessary. One of the first steps in designing a system, after the definition of an accident or loss and the drawing of boundaries around the subsystems, is to identify the hazards that need to be eliminated or controlled by the designers of that system or subsystem. 

The most widely used existing hazard analysis techniques were developed fifty years ago and have serious limitations in their applicability to today s more complex, software-intensive, sociotechnical systems. This chapter describes a new approach to hazard analysis, based on the STAMP causality model, called STPA (System-Theoretic Process Analysis). 

The use of CAST does not lead to identifying single causal factors or variables. Instead it provides the ability to examine the entire sociotechnical system design to identify the weaknesses in the existing safety control structure and to identify changes that will not simply eliminate symptoms but potentially all the causal factors, including the systemic ones. 

Another factor that made these large-scale sociotechnical systems possible was a social innovation in business the emergence of the multi-unit, professionally managed, vertically integrated, hierarchically organized modern business firm. See Chandler (1977). 

The high correlations between team-based factors and other PSF categories may also be an indicator of the strong role that teams play in commercial nuclear power. For most operations and maintenance tasks there is either direct teamwork or some level of review to ensure that tasks are completed correctly. The team has a significant role in almost every aspect of commercial power and it is natural that the team would correlate with many aspects of the sociotechnical system. 

We beheve responsibilities are a natural form of expression for risk analysis within complex sociotechnical systems. We have developed the technique of responsibihty modelling, an approach which allows stakeholders to explore the hazards and associated risks of a given system in a structured and logical manner. These models can then be used to mitigate or avoid the risks associated with misunderstandings, and provide support for the analysis of potential process change. 

Despite some similarities, responsibility modelling differs from goal based techniques. Whilst the notion of responsibility modelling may be viewed as incorporating the specification of objectives to be achieved, there is also an acknowledgment that in complex sociotechnical systems, the achievement of an objective (i.e. the discharge of responsibility) is subject to a range of constraints and that even with the best efforts of an... 

Monitor indicators reflect the potential and capacity of the organisation to perform safely. The indicators monitor the functioning of the system. These indicators seek to measure the internal dynamics of the sociotechnical system and provide information on the activities of the system. Information should be provided not only about safety management initiatives but also about the persoimel, work processes, stractures and technology in the system. Cultural issues such as norms, values and shared practices should also be incorporated into monitor indicators. Figure 9.2 illustrates the ways in which safety indicators can be used to provide information to support safety management. 

In conclusion, proactive safety indicators either irtfluence safety management priorities and the chosen actions for safety improvement or provide information about the dynamics of the sociotechnical system (not merely about the functioning of safety barriers and absence of harm). These proactive indicators are respectively labelled drive indicators and monitor indicators in this chapter. Safety indicators should be capable of measirring (morritor indicators) or facilitating (drive indicators) the presence of organisational attribrrtes necessary for ensuring adequate patient safety. 

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