Dynamic Systems Development Model (DSDM) - Type of Agile Methodology

The Dynamic Systems Development Model was developed in the U.K. in the mid-1990s. DSDM favors the philosophy that nothing is built perfectly the first time and looks to software development as an exploratory endeavor.

The nine principles of DSDM are:
- Active user involvement.
- Empowered teams that the authority to can make decisions.
- A focus on frequent delivery of products.
- Using fitness for business purpose as the essential criterion for acceptance of deliverables.
- Iterative and incremental development to ensure convergence on an accurate business solution.
- Reversible changes during development.
- Requirements that are baselined at a high level.
- Integrated testing throughout the life cycle.
- Collaboration and cooperation between all stakeholders.

Requirements are baselined at a high level early in the project. Rework is built into the process, and all development changes must be reversible. Requirements are planned and delivered in short, fixed-length time-boxes, also referred to as iterations, and requirements for DSDM projects are prioritized using MoSCoW Rules:
M – Must have requirements
S – Should have if at all possible
C – Could have but not critical
W - Won’t have this time, but potentially later
All critical work must be completed in a DSDM project. It is also important that not every requirement in a project or time-box is considered critical. Within each time-box, less critical items are included so that if necessary, they can be removed to keep from impacting higher priority requirements on the schedule.
The DSDM project framework is independent of, and can be implemented in conjunction with, other iterative methodologies such as Extreme Programming and the Rational Unified Process.