Using Earned Value Management (EVM) in Spiral Development

Earned Value Management (EVM) helps managers to plan, monitor, and control the development and evolution of custom developed software-intensive systems. EVM assumes a waterfall development model. However, to meet the demands for today's complex, dynamic systems, certain trends have emerged. First, projects no longer develop all components of a system as custom components. Instead, projects use pre-existing, off-the-shelf packages, components, or entire systems, potentially with custom components. A second trend is a realization that often requirements are not known in detail at the start of a project and must evolve efficiently in response to changing needs and technology. A further trend (often in response to the first two trends) is the move to other development models, such as spiral or iterative development processes. Spiral development processes can better support 1) the required discovery of what users want and 2) negotiation to reconcile what engineers can quickly and reasonably assemble from pre-existing and custom components. While projects have applied EVM to spiral development projects, the results have not been uniformly satisfying. This report explores the fundamental challenges in using EVM with spiral development processes and proposes adaptations to some EVM principles to render it more suitable for today's software-intensive systems.