Conclusion

We have discussed the roles in an XP project as defined by Kent Beck. Based on our experience, we split the XP customer role into two roles: user and client. The user is the source of application knowledge, while the client defines the project goals and supplies the money for the project. Both parties must be integrated into the development project. We have shown how this can be done with the help of modified story cards, projects stages, baselines, and an adapted planning game.

We do not suggest using all the new instruments presented here for every project. They should be used as part of an inventory or a toolbox, together with the familiar techniques defined by XP. The instruments should be used as required for the project in hand. If the project is not complex, there is no need to burden the project with the additional roles and document types. But if the application domain or the project is highly complex, the sketched extensions to XP are worthwhile.

Selection of the proper instruments from the toolbox may be difficult for the project team because we are not yet able to provide detailed guidelines. Evaluating project experience to provide such guidelines for tool selection will be one of our future tasks.