"Agile’s biggest threat to system quality stems from the fact that it’s a method proposed by programmers and mainly addresses the implementation side of system development. As a result, it often overlooks interaction design and usability, which are left to happen as a side effect of the coding. This, of course, contradicts all experience of the last 30 years, in which user experience’s importance in system development has steadily increased as we moved from mainframes to PCs to the Web. As the user base and the use cases have expanded, the need for top-notch usability has grown. To construct a quality user experience, development teams need interaction design and usability methods. For smaller teams, this doesn’t necessarily require dedicated designers and usability professionals. It’s perfectly feasible for developers to do interaction design and usability. But a team must recognize these two activities as explicit development methodology components, whether the people doing them have design or usability as their main job or simply as one of several roles they perform. For a project to take interaction design and usability seriously, it must assign them “story points” (i.e., resources) on an equal footing with the coding. Another issue is that, with Agile, a product’s development is broken down into smaller parts that are completed one at a time. Such an approach risks undermining the concept of an integrated total user experience, where the different features work consistently and help users build a coherent conceptual model of the system. At worst, the user interface can end up resembling a patchwork. To address this, teams can design storyboards and prototypes that embed the user interface architecture and use these tools as reference points for designing individual features. To avoid spending too much time up front, teams can design low-fidelity prototypes — such as paper prototypes — that don’t require coding. Just like we’ve always advocated. Agile teams typically build features during fairly brief “sprints” that usually last around 3 weeks. With such tight deadlines, developers might bypass usability because they assume there’s no time to do testing or other user research."
— Agile Development Projects and Usability (Jakob Nielsen’s Alertbox)
