Productivity Trends in Incremental and Iterative Software Development

In the literature review, we have studied more than two dozen sources covering both software productivity and incremental and iterative development. In this section, we will provide a brief overview of some of these studies and our summary of potential drivers that may influence productivity in incremental and iterative development.
We begin with classic definition on software productivity. Boehm defines software productivity as outputs produced by the process over inputs consumed by the process [9]. A list of productivity drivers have been identified by many researchers: these drivers include resource constraints, requirement volatility, use of software tools, program complexity, customer and user involvement, personnel experience and capabilities, etc.
Scacchi [16] divided these drivers into three attribute lists: software development environment, software system product, and project staff attributes. He also described the desired conditions for each attribute in order to achieve high productivity.