Systems engineering

Abstract

Despite advances in engineering knowledge and technology the everyday experience of the engineered world provides, all too often, evidence of failure as well as success. For example, as a literate and healthy human is it unreasonable to expect: • to be readily able to set the alarm function on my digital watch and to be confident that it will work? • to be able to read the instructions on food packaging? • to correctly change batteries, first time, on an electric toothbrush? • not to have to move every few minutes to prevent the office being plunged into darkness by a motion sensitive, power-saving system? • to have my 'patient's notes' present at the same time as myself in an otherwise high-tech clinic? All these problems, and more, have beset our group recently.The list is long, the explanation occasionally obvious (for example, the batteries were inserted incorrectly because it is almost impossible to see the polarity signs embossed on the internal base of the toothbrush battery casing) but the implications for engineering are enormous. Quite simply, they force us to ask whether the engineering process itself is correct. All engineered environments and artefacts have human involvement. Even so-called 'fully automated processes' are anything but that. On analysis we find that they are specified and designed by humans, tested by humans, commissioned by humans, maintained by humans, and subsequently decommissioned and disposed of by humans.The need for a systematic approach to design that is inclusive of 'the human factor' is evident, but is it acted upon? Even when the 'human factor' in the system is considered, it is often forgotten that whilst humans may come as individuals, they always work as groups, teams, organisations and, even, societies. Understanding the resultant needs, behaviours and attitudes is integral to systems engineering. Pheasant (1996) identified five fallacies of engineering design (Table 3.1).The common thread that runs through them all is the need to recognise that design, to be successful, must adopt a systems approach. How then to avoid such traps and develop systems that truly reflect modern thinking and knowledge? The following sections present an introduction to systems engineering and ergonomics, focusing on the way in which they should influence the design process. Examples are presented to illustrate the key issues. Many are from the healthcare industry, where safety can only assured if a systems approach is adopted.