Posted by: bbannan | March 9, 2011

Usability or Not Usability that is the Question….. Matt

When thinking about how to evaluate usability it is important to determine exactly what usability means. This is because to different sects of people and vocations , usability means different things. Usability metrics need to be able to encompass both the general and specific areas of usability. Usability, according to Carter and Schneiderman, is a general blanket term that deals with Visual design, information architecture, navigation design, Interaction design, and user interface design.

Kuniavsky, suggests using not fully functioning prototypes ( paper, wireframes etc.) to develop usability metrics.  At first this seemed a little wrong to me.  How are you supposed to test something that doesn’t work the way it is supposed to yet?  It would be like trying to determine if the food you are eating is delicious before the server brings it to you in a restaurant.  However, looking at the new definition of usability I saw that I was only concerned with one aspect of usability; interaction design.  All of the other methods; visual design, information architecture, navigation design, and user interface design can all be done pre-production.

This amount of variation in evaluation means that usability can be checked throughout many stages of the design process.  In fact, both in the website and the power point presentation resources it states that often times a finished product is not necessary to do gather usability information. It is possible design and evaluate a product without even actually physically creating it. This is a fairly new idea but it is one that is gaining popularity and is especially important to our class.

As described above, there are more specific sub areas of usability for which different tests and evaluation are needed. However this does not mean that there are not tools for evaluation that can be used too look at usability as a whole. It is called TAFEI or Task analysis for Error identification. The identification of errors is an analysis  that deals with all aspects of usability . TAFEI allows you to do this look at the all the information that the user would use to operate or learn a system or device and to determine ahead of time where errors may occur.  This is very useful with the repetitive process of design because it allows you to see errors before stages of production and other analysis begin.

When looking at usability it is important to understand what testing metrics work for the sub areas of usability and which ones work for all aspects of usability. Knowing this difference and being able to apply it will make designing evaluation tools and reiterative design that much easier.

If anyone is interested in TAFEI you should check out these books.

Kirwan B.,& Ainsworth L.K. ( 1992). “A guide to task analysis”.
Boca Rotan, Fl.  Taylor and Francis Group LLC.,

Stanton, N., Hedge, A., Brookhuis K., Salas S. & Hendrick, H. (2005). “Handbook of Human Factors and Ergonomics Methods”.
Boca Rotan, Fl.  Taylor and Francis Group LLC.,



  1. Matt, thanks for your excellent post. It really opened my eyes to the many aspects of usability. The thought you express about Kuniavsky’s usability idea and the question of how can you test something that’s not complete really resonated with me. As I read your thoughts about usability having many aspects and having multiple methods, this clicked with me in understanding the multifaceted nature of usability. I was definitely stuck in the singular mind frame of only thinking about interaction design as I read the other resources and Kuniavsky. Thanks for your clarification.

    I’m very interested to learn more about TAFEI. So far, I found this site ( that talks about TAEFI as a cognitive engineering method and it’s interesting to observe some of the method steps that are shown. Have you had any prior experience using TAFEI? I’m also curious if you encountered any arguments against TAFEI in your search and what they specifically were.

    Thanks again for your post,

  2. To echo Andrew’s comment, thanks for this really helpful post, Matt. I’ve been quite interested in usability for a while now, but I have to admit I too was leaning mostly toward the consideration of interaction design. I think this expanded view of usability will definitely help my group as we’ve planned a usability test for round 2 of testing. Now I’m thinking we might even organize our questions (at least from our point of view) using the additional components you mentioned like visual design, information architecture, and navigation design. Thanks again.

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