As one of the building blocks of my PhD thesis, I have developed a novel instrument for measuring the usability of web interfaces, which is simply called Inuit—the Interface Usability Instrument1. This was necessary because a usability instrument that is suited for the automatic methods for Search Interaction Optimization I have developed in my PhD project must fulfill three particular requirements, which are not met by any existing instruments:
(R1) A minimal number of items.
(R2) Items with the right level of abstraction for meaningful correlations with user interactions recorded on the client.
(R3) Items that can be applied to a web interface in terms of a stand-alone webpage.
The Instrument
Inuit has been designed and developed in a two-step process: First, over 250 rules for good usability from established guidelines and checklists were reviewed to identify a set of common underlying factors (or items) according to R2. From these underlying factors, a “structure” of usability based on ISO 9241-11 was created, which was then shown to 9 dedicated usability experts in the second step. The experts—all of which were working in the e-commerce industry—reviewed the given “structure” and proposed changes according to their perception of web interface usability. Finally, seven items have been identified:
- Informativeness
- Understandability
- Confusion
- Distraction
- Readability
- Information Density
- Reachability
These items can be translated to, e.g., the following yes/no questions for use in a questionnaire for determining the usability of a webpage:
- Did you find the content you were looking for?
- Could you easily understand the provided content?
- Were you confused while using the webpage?
- Were you distracted by elements of the webpage?
- Did typography & layout add to readability?
- Was there too much information presented on too little space?
- Was your desired content easily and quickly reachable (concerning time & distance)?
Conclusions
A confirmatory factor analysis based on a user study with 81 participants has proven that our instrument reasonably well reflects real-world perceptions of web interface usability. Inuit was first introduced at the workshop “Methodological Approaches to Human–Machine Interaction”, which was held as part of the 2013 Mensch & Computer conference. The corresponding paper is named Towards Metric-based Usability Evaluation of Online Web Interfaces (full-text here). The final version of the instrument has been presented at this year’s International Conference on Design, User Experience and Usability (DUXU), which has been held in Los Angeles. The full research paper is titled Inuit: The Interface Usability Instrument and available via Springer (full-text here).
Future Work
In the future, I intend to transfer Inuit into the context of my current work. That is, I intend to use it for evaluating the web interface of HoloBuilder, which enables users to create 3D content for the web, in contrast to the usual 2D content that is consumed nowadays. It will be particularly interesting to see whether both, 2D and 3D web interfaces can be meaningfully evaluated using the same minimal instrument. Furthermore, Inuit will be applied in the context of the research on evidence-based computing that is happening at the VSR research group at Technische Universität Chemnitz.
P.S.: Thanks a lot to Viet Nguyen for the awesome Inuit logo! 🙂
1 Please note the small caps!
2008 – Tales of Design & User Experience 