| Software production is on the critical path of increasingly many program abilities to deliver effective operational capabilities. This is due to the number, complexity, independence, interdependence, and software-intensiveness of their success-critical components and interfaces. The estimation parameters and knowledge bases of current software estimation tools are generally good for stable, standalone, single increment development. However, they do not fully account for the degrees of program and software dynamism, incrementality, coordination, complexity, and integration. These phenomena tend to decrease software productivity relative to the cost model estimates made for the individual software components and for the overall systems, but it is difficult to estimate by how much.;Incremental software development generally involves either adding, modifying, or deleting parts of the code in the previous increments. This means that if a useful system is to be built, the maintenance that will have to go into previous increments will take away productivity from the later ones.;This research tests hypotheses about a phenomenon called Incremental Development Productivity Decline (IDPD) that may be more or less present in incremental software projects of various categories.;Incremental models are now being used by many organizations in order to reduce development risks while trying to deliver releases of the product on time. It has become the most common method of software development with characteristics that influence the productivity of projects.;Different ways of measuring productivity are presented and evaluated in order to come to a definition or set of definitions that is suitable to these categories of projects. Data from several sources has been collected and analyzed, and hypotheses tested about the degree of IDPD and its variation by increment and category. The results indicated the existence of an IDPD phenomenon, that its magnitude varies by application category, but that it tended to vary from increment to increment. |
