Optimising Content Clarity for Human-machine Systems1

1. Introduction Increasingly, members of the public are exposed to human-machine systems that are many times more complex in functionality and interactivity than previous systems (Weir, 1991). Often, these systems are domestic appliances, such as digital video cameras or recordable DVD players, and the end-users take the role of operators, seeking to assimilate, command and control their newly acquired technologies. Although, unlike commercial process control environments, systems at the domestic level pose little risk to life and limb, there are similarities in the challenges facing both types of operator. In particular, each will be reliant to some degree upon the readability and comprehensiveness of associated documentation. Whether such support is available on-line, in the form of interactive help systems, or off-line, in the form of associated technical manuals, each operator relies upon the clarity and comprehensibility of its content. Inevitably, there are settings in which the adequacy of afforded information proves critical. Dubay (2004) states that, due to poor comprehension of installation manuals, 79 to 94 percent of child safety seats are installed improperly-a fact that has aggravated the rate of infant deaths in traffic accidents. The inadequacy of technical documentation addressing the complexity of child safety seat installation is a stark pointer to the scale of difficulty inherent in documentation design.