The ultimate purpose of all serious software applications is to produce knowledge that has a positive impact on the real world. A major factor that influences the success or failure of information systems is the quality of the data they manage and produce. The dependence of software systems on data quality leads to serious causes for concern:
Modern software projects need to be highly agile to accommodate the changing requirements of clients; especially those who don't fully understand what they need. The fixed specification approach advocated by the waterfall model is no longer adequate for most projects; the waterfall model being a formal set of project phases that start with the requirements definition and progress through to design, implementation testing and review in a fixed order.
It is rare for clients to communicate their specification changes in relation to the entire software system, meaning that they will ask for changes to a specific part of the system...