Factoring humans into procedures

In 1987, the Institute of Nuclear Power Operations (INPO) completed a Human Performance Evaluation System study of events reported between 1985 and 1987. INPO attributed 360 events in the study to human performance errors. Deficient procedures were the largest category of causes for human performance errors (22.2%). The authors illustrate that human factors techniques used to upgrade control rooms can be used to upgrade procedures. The fundamental approach is to engineer each page or each complement of pages in a double-sided document by treating it as a single display on a control room panel. The approach takes advantage of the fact that reading a procedure, like operating a control panel, is a visual as well as a mental activity. Four techniques for applying this approach are reviewed: presenting information in small block (or fields), presenting information, using the mental templates of the performer, and matching the physical features of the plant. Examples in which combinations of these techniques are used are presented.<>