Ergonomics for Interaction Designers: Part 3 | | |
This is the third and final part of this introductory "mini-series". Part 1 introduced the value of ergonomics to interaction designers, and Part 2 discussed some of the challenges and methods of anthropometric design for a broad range of users. Now I am going to focus on how to identify ergonomic issues in observational and lab testing contexts. | | |
Qualitative Observations Issues in Field Research | | |
While interaction designers will typically lack special training in ergonomic assessment methods, most will have some degree of familiarity, if not significant experience with user-centered methods including contextual observation (aka ethnographic field research) and usability testing. All of these methods share objective observation as a common data gathering method, and really only vary in the particular variables or characteristics that are the subject of study. And while anthropometric data is intrinsically quantitative, qualitative observational research can be applied to identify ergonomic issues. With these factors in mind, I've developed a basic set of ergonomic observational criteria to use as guidelines when evaluating design fit. The guidelines are inspired by Stephen Pheasant's cardinal rules of anthropometrics, extended to qualitative field research. | | |
Pheasant advised focusing on Reach, Clearance, Posture and Strength. I'll explain how these can be applied to a consumer electronics device, the InterAction Labs SQWEEZE Game Controller, pictured above. The SQWEEZE is an accessory to the Nintendo Wii - inserting a Wii controller into the SQWEEZE unit allows the user to apply push/pull forces for gaming - think of drawing a bow string to shoot an arrow, for example. While the SQWEEZE was well designed by ergonomics standards, it makes for a good example for explaining the four anthropometric characteristics: | | |
Reach typically refers to extending the arms and finger for effective control without over-extension. In the case of the airport Kiosk discussed in Parts 1 & 2 there's a clear potential for placing the touch screen at a height or distance that would be difficult for some people to access effectively. That type of reach is a non-issue for handheld devices like the SQWEEZE, but other types of reach can come into play. In the case of two-handed devices, the distance between the handles needs to be appropriately set to accommodate a comfortable grip. For the SQWEEZE, this distance actually varied between the push and pull positions as the handles flexed inward and outward respectively. Similarly, the diameter of the handles affects the user's ability to adequately wrap his or her fingers around them; a smaller-scale, but just as important, reach issue. | | |
