All software engineering methodologies have their strengths and weaknesses. Agile Methods and Interactive/User-Centered Design are certainly no different.
Classical Agile Methods aspire to deliver a light feature set of working software into the hands of the customer as quickly as possible. Thus avoiding much of the resource consuming, pre-development requirements employed in methodologies such as the Waterfall methodology.

Interactive/User-Centered Design, on the other hand, strives to understand the users needs, tasks, and user contexts at a fairly comprehensive level. This means that prior to initial coding a fair amount of upfront research is needed to facilitate the Interactive/User-Centered Design. Although this seems similar to the Waterfall approach, the difference is that the Waterfall approach seeks to simply gather requirements, where as Interactive/User-Centered Design seeks to uncover the underpinning user contexts to discover requirements.

Both of these methodologies have the same ultimate goal; build a product that is what the customer/user actually wants and needs. A most worthy goal indeed! However, both of these methodologies are not without specific problems and obstacles. For instance, Agile looks at the immediate in terms of development, on the other hand Interactive/User-Centered looks at the overall long term picture in terms of development. One loses sight of the overall vision, whereas the other loses sight of the immediate.

This brings me to the nature of my research. Can, if, and when or when not is it possible for both Agile and Usability be integrated to spawn a hybrid methodology to perhaps circumvent some of the governing obstacles described above that limit each methodology?

My intent is to study these two methodologies from three perspectives in terms of user interface (UI) development. First, study situations where both methodologies, Agile Methods and Interactive/User-Centered Design, are employed. Second, study situations where Agile Methods are used but no Usability specialist is present. Finally, study situations where Usability specialists are present and the development methodology is not Agile. From this I hope to derive more precise questions to further understand if these two methodologies are compatible as well if development is less or more productive when they are amalgamated.