Writing usability requirements and metrics
Categorised under: Metrics & ROI, Usability & user-centered design
Janet M. Six has written an article on writing usability requirements and metrics. To quote:
I think we overemphasize metrics when it comes to usability. They often introduce problems in terms of the validity and reliability of the data. First, ask whether a metric is a valid measure of usability. For example, the amount of time it takes to perform a task is often a usability goal—as in your example Six out of ten novice users shall perform task X in Y minutes. What if all of the participants took more than Y minutes to complete the task, but everyone said, ‘This is the best application for doing this task I have ever experienced. I’m recommending this product to all my friends.’ Does the product fail to meet the requirements regarding that task? What if all participants perform the task in less than Y minutes, but everyone says, ‘That was a horrible experience. I would never buy this product.’ Does the product satisfy requirements?
James Robertson is the Managing Director of 