Don't forget the
human interface

Many of the reports we see and hear about product failures are blamed on the machine. What about the operator? There are many factors to consider in product design, and an engineer must be concerned with every one of them or the design will be flawed. One of those factors is the human interface. A recent experience brought this home to me. My girlfriend, Niamh, had laser eye surgery performed. She was a little concerned about the procedure, having heard there was a small failure rate, but was generally confident. I was allowed to attend–to hold her hand and keep her calm. I wish I had someone to keep me calm. Here we were in a posh Manhattan skyscraper clinic, and I felt like I was in the middle of an episode of The Three Stooges . The couch Niamh was lying on wasn't properly positioned, and the doctor had trouble keeping Niamh's eye in the laser reticule. At one point, one of the assistants had to hold Niamh's chin with her bare hands to try to keep her head from moving. In the middle of all this, a woman was bustling about in street clothes–I later found out she was the person who owned the laser itself. Sad to say, the surgery did not result in a completely satisfactory outcome. Although failure rates have often been quoted, I haven't seen any of the problems from this procedure attributed to human error. However, I believe that if the couch had been set up properly and the doctor had waited to ensure proper positioning, the errors in surgery would probably not have happened. I blame the doctor for not being more assertive in her needs. I blame the owner of the machine for not properly operating it. And I blame the designer for not putting a foolproof couch with proper head restraints on a device intended to shoot laser beams into people's eyes. When you design a device, you must take into consideration that the operator, no matter how well educated, may still use it stupidly. Design must not only take environment and application into consideration, but must also consider the human element. We can all bring up examples of design without a good user interface. The problem is remembering that a good user interface is as important, if not more so, than any other aspect of a design, for if a device cannot be properly operated, it is often less than useless. Alix L. Paultre, Associate Editor