Ergonomics is the application of scientific information concerning humans to the design of objects, systems and environment for human use. Its role in the design process is to look out for the interests of 'end users' and to ensure that designs meet their needs.

Readers will be familiar with many everyday irritations such as:

• Why can only tall people reach things from the top shelf at the supermarket?
• Why does my mouse make my wrist ache?
• Why can't I work out how to set my video?
• How do I get my wheelchair onto this bus?
• Why do none of the options on the call centre menu seem to apply to me?
• Why does my head touch the roof of this car?
• Why can't they make the print bigger in these product instructions? Where's the on/off switch on this thing?
• How on earth do I find out how to use this website?
• Often problems such as these are the result of poor ergonomics — a failure to identify people's needs and provide solutions appropriate to their capabilities and characteristics.

Broadly, ergonomics addresses the following issues:

• Safety. Are these railings high enough to stop someone falling over them? Will repeatedly lifting this widget onto a conveyor belt hurt someone's back? Will the control room operator notice the alarm indicator for imminent nuclear meltdown?
  
• Effectiveness. Will this wheelbarrow allow me to shift more concrete? Will shoppers on my e-commerce site be able to find what they want? Can I launch my surface-to-air missile in sufficient time to intercept the incoming enemy fire?
  
• User Experience. Is this kitchen knife a joy to use? Is finding interesting books on this site such a breeze that I'll come back time and time again? Do I enjoy the comfort and efficiency of my work environment so much that I can hardly keep away from it?

In practice, of course, these aspects tend to be interrelated — for example, an Air Traffic Control system which allows the controller to identify and avert potential conflicts effectively is safer for the passengers and less stressful for the controller.

The ergonomics approach uses information from psychology (cognitive, behavioural, perceptual, social, organisational), anatomy and physiology to address these issues. It can be applied to something as small as a pair of tweezers or as large as an aircraft carrier.