Thursday, May 11, 2006


customers, users and agile software

In an effort to become less ignorant of agile software approaches, I recently listened to a podcast with Alistair Cockburn on the topic. What agile seems to do well is get users involved in the shaping of the functionality of a system. It can do this by offering a tangible prototype for users to react to. Too often, functionality is shaped entirely by business requirements documents, which are at a very high level. Specific functional requirements that users might need can be overlooked in less iterative processes that emphasize development of high level functional requirements, and if these needs are uncovered later in the process, they can be hard to "bolt on."

The podcast also sheds light on how agile approaches conceive of customers. Agile is indeed "customer focused", but customers are not entirely the same as what usability professionals refer to as users. Cockburn speaks of customer collaboration over customer negotiation. I wholeheartedly support these sentiments, which are good business practice, as well as good design practice. But usability professionals would never speak about "user collaboration over user negotiation." Customers -- who include people who buy/commission software -- aren't necessarily users, and the terms customer and user cannot be used interchangeably. So talking about customers, who Cockburn sees as being both "sponsors and end users", can sometimes obscure distinctions usability professionals would make between different end user profiles (abilities, attitudes, environments, etc.). Even if all end users have the same basic functional requirements (what the system does), it does not follow they have the same user requirements (the way the system needs to do it to meet user needs.)

The central tenet of usability is to test with a representative user population. Here I think usability testing and agile functional testing have widely different approaches. I have suspected that agile approaches lack the thoroughness of usability in seeking wide participation of users in the process, because the needs of functional testing (find functional limitations) are fundamentally different from usability testing (find interaction limitations.) Usability professionals, even when using lightweight "discount" approaches, might need to test 5 people to get meaningful understanding of interaction issues and problems that need refinement. Cockburn sees a successful "access to a customer" under an agile scenario as being an "hour or two" a week -- considerably shorter than usability approaches, and probably not involving as many individuals either. He also emphasizes the importance of access to "expert users." Experts are indeed useful for functional specifications, but not necessarily ideal for determining user requirements.

For those of us in the usability community, the podcast highlights some of the attitudes of the agile orientation, particularly the aversion to "process heavy" approaches. Notwithstanding the debate and diversity in the agile development community, agile developers generally embrace methodological minimalism and skepticism toward formalism, for example, asking for a justification of the value of non-code related activities such as documentation. Within agile, there is lively discussion over which activities are essential and which ones aren't. It remains to be seen if agile software developers will consider user centered design as another "process heavy" activity.

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