The DSDM is derived from the linear Software Development Methodology (SDM) model, which originated in the 1990s. It was an answer to the problem that, in linear methods, the functionality to be developed is often available too late as a whole. If the functionality to be delivered can be divided into sub-functionalities, these sub-functionalities can be delivered separately. We call this incremental system development or step-by-step development. In the beginning you want to find out which functionality can be split off. This means that the first two phases from the waterfall approach are completed, but only when the partial functionalities are clear can these be developed step by step in parallel.

DSDM is more than just applying iterations at development stages. All of the remaining phases after analysis are iterative. In addition, the division of phases looks slightly different. In contrast to the linear development model, it is also possible to go back to previous phases.

The phases within DSDM are structured as follows:

• Feasibility study
• Business analysis
• Functional model iteration
• Design and construction iteration
• Implementation

Timeboxing is one of the core practices used in DSDM to control each stage, which is combined with better prioritization with MoSCoW. We will explain this in the following section.