Page 303 -

286 Chapter 10 Sociotechnical systems

KEY POINTS

Sociotechnical systems include computer hardware, software, and people, and are situated within
an organization. They are designed to support organizational or business goals and objectives.
Human and organizational factors such as organizational structure and politics have a
significant effect on the operation of sociotechnical systems.
The emergent properties of a system are characteristics of the system as a whole rather than of its
component parts. They include properties such as performance, reliability, usability, safety, and
security. The success or failure of a system is often dependent on these emergent properties.
The fundamental systems engineering processes are system procurement, system development,
and system operation.
System procurement covers all of the activities involved in deciding what system to buy and who
should supply that system. High-level requirements are developed as part of the procurement
process.
System development includes requirements specification, design, construction, integration, and
testing. System integration, where subsystems from more than one supplier must be made to
work together, is particularly critical.

When a system is put into use, the operational processes and the system itself have to change
to reflect changing business requirements.
Human errors are inevitable and systems should include barriers to detect these errors before
they lead to system failure. Reason’s Swiss cheese model explains how human error plus latent
defects in the barriers can lead to system failure.

FURTHER RE ADING

‘Airport 95: Automated baggage system’. An excellent, readable case study of what can go wrong
with a systems engineering project and how software tends to get the blame for wider systems
failures. (ACM Software Engineering Notes, 21, March 1996.)
http://doi.acm.org/10.1145/227531.227544.
‘Software system engineering: A tutorial’. A good general overview of systems engineering,
although Thayer focuses exclusively on computer-based systems and does not discuss
sociotechnical issues. (R. H. Thayer. IEEE Computer, April 2002.)
http://dx.doi.org/10.1109/MC.2002.993773.
Trust in Technology: A Socio-technical Perspective. This book is a set of papers that are all
concerned, in some way, with the dependability of sociotechnical systems. (K. Clarke,
G. Hardstone, M. Rouncefield and I. Sommerville (eds.), Springer, 2006.)

‘Fundamentals of Systems Engineering’. This is the introductory chapter in NASA’s systems
engineering handbook. It presents an overview of the systems engineering process for space