Human Reliability versus Ease of Use

I just read the panel description for a panel from this year’s Human Factors and Ergonomics Society Conference. It was on the relationship between human reliability and usability. There were some interesting perspectives discussed. The panelists all see a mistaken perception among many practitioners that there is a disconnect.

Both groups would prefer a design that maximizes both safety and ease of use, but we all know that we often encounter tradeoffs between them. Usability practitioners want to make things easy as the primary goal. This means making things so simple that they become automatic and require little or no conscious attention.

Reliability practitioners want to interject more consciousness to prevent, or at least reduce, skill-based errors. This is important because skill-based errors are often the most pervasive when we are dealing with experienced workers or domain experts. We get so used to putting our jobs on cruise control that we are susceptible to errors that are more due to a lack of focused attention than to any error in judgment.

This leads to a layered design model that makes sure both objectives are considered. You start out considering them separately but with good communication so that you don’t develop totally different design approaches. And as the design gets closer to completion (i.e. higher fidelity), the two objectives get more fully integrated.

This is very important in domains like nuclear power plant design, air traffic control, and the military. But it is also important in situations like my previous post (e-commerce web sites).