A comparison of methodologies for designing for human variability
In the design of artifacts that interact with people, the spatial dimensions of the user population are often used to size and engineer the artifact. The variability in size is used to indicate how much adjustability or how many sizes are required to accommodate the intended user population. However, size is not the only predictor of this kind of interaction. Variability that is not predicted by body dimensions can be considered “preference”. Designing for human variability requires taking into account variation in preference as well as the range of body dimensions, leading to products that are more accessible for more people, safer, and less expensive. Failure to include a preference component can produce misleading results that under- or over-approximate accommodation and prescribe inappropriate amounts of adjustability. This thesis, prepared in accordance with the guidelines of the Schreyer Honors College, compares traditional design methods that consider only anthropometry with a newer method that also takes preference into account. A design example is presented to illustrate the methods: determining the required range of seat height of an exercise cycle to fit a prescribed portion of the target user population. The thesis culminates with a new process for designing products for human variability that makes use of the new methodology, along with a second case study that illustrates the steps of the new process: determining the minimum size of a laptop computer keyboard to fit a prescribed portion of the target user population.