This paper is about general iterative user interface design and it shows the successes of using this process. The improvement in overall usability was shown to be 165% from the first to last iteration, and the median improvement was 38%. They found that there should be 3 iterations since more iterations could actually decrease the usability if the usability engineering process was focused on improving other parameters.
The Benefits of Iteration
Nielsen presents a graph that shows that usability increases directly after each iteration until it eventually hits a plateau. A con is that sometimes after an iteration, usability decreases since new usability problems maybe introduced. The pro is that they can usually be ironed out shortly after. He suggests that interface reconceptualizations have not been studied on projects that were completed by an individual.
An example from later in the paper (Table 5) saw a dramatic decrease Time on Task, Subjective Satisfaction and increase in Errors Made and Help Requests from version 2 to 3 and 3 to 4. However, by version 5 they were all improved by the final version. A big con could be if a project can’t be updated before the final version and it would be better to have version 1 versus having version 3.
From my perspective, iterative design is natural, and projects will follow this without even the designers trying to. Building several different designs and comparing them side by side and then choosing the best will also work, but the chosen version would be improved through an iterative process. Choosing between multiple designs then using iterative improvements on the chosen design, using features from the different versions is the best method for design.
Conclusions
The number of iterations cannot be chosen in advance since the version from iteration 3 might be worse than the first but with two more iteration could be much better than the first. It would be a big con to try to chose the exact number of iterations before hand and a large pro to allow this number of iterations to be dynamic.
Discussion
- Iterative usability design for individuals instead of teams
- Alternative to iterative design: iteration is natural
- Nielsen writes about iPad & touches upon multi-touch in the paper:
- http://www.useit.com/alertbox/ipad.html
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