Software Development Lifecycles - Progressive Development Lifecycle Models

The sequential V and waterfall lifecycle models represent an idealised model of software development. Other lifecycle models may be used for a number of reasons, such as volatility of requirements, or a need for an interim system with reduced functionality when long timescales are involved. As an example of other lifecycle models, let us look at progressive development and iterative lifecycle models.


A common problem with software development is that software is needed quickly, but itwill take a long time to fully develop. The solution is to form a compromise between timescales and functionality, providing "interim" deliveries of software, with reduced functionality, but serving as a stepping stones towards the fully functional software. It is also possible to use such a stepping stone approach as a means of reducing risk.

The usual names given to this approach to software development are progressive
development or phased implementation. The corresponding lifecycle model is referred to as a progressive development lifecycle. Within a progressive development lifecycle, each individual phase of development will follow its own software development lifecycle, typically using a V or waterfall model. The actual number of phases will depend upon the development.