Differences in Approaches

Besides their aforementioned similarities, the various Agile approaches also differ in many areas.

Unit of work

Agile approaches differ in the unit of work they propose. Extreme Programming and Scrum use user stories. Feature-driven development uses features. Smart uses smart use cases and OpenUP regular use cases. DSDM uses a prioritized requirements list. However, none of the Agile approaches are stuck in a prescribed unit of work. We’ve participated in DSDM and Scrum projects that used smart use cases.

Preparation

In lightweight Agile, a project starts when the backlog is established. Little attention is given to project preparation. Middleweight approaches do focus on this preparation. They use preparatory iterations to determine the objectives, scope, and stakeholders. An inventory is often made of the requirements and work items, a first architecture drafted, estimates calculated, and a project plan written.

Estimating

Estimating happens at different moments in the various Agile approaches. Lightweight Agile approaches only draft a very rough estimate at the start of the project and estimate accurately only when the work items for an iteration are known. Middleweight approaches create a thorough estimate during the project preparation. A second approach is a wise approach compared to the first approach.