Incremental Commitment Model

Barry Boehm e Jo Ann Lane: "Using the Incremental Commitment Model to Integrate System Acquisition, Systems Engineering, and Software Engineering", in CrossTalk, October 2007

Many projects have difficulties in integrating their hardware, software, and human factor aspects.

In comparison to the software-intensive RUP, the ICM also addresses hardware and human factor integration. It extends the RUP phases to cover the full system life cycle: An Exploration phase precedes the RUP Inception phase, which is refocused on valuation and investment analysis. The RUP Elaboration phase is refocused on architecting (a term based on describing concurrent development of requirements, architecture, and plans),
which adds feasibility evidence; the RUP Construction and Transition phases are combined into the Development phase; and an additional Operation phase combines
operations, production, maintenance, and phase-out. Also, the names of the milestones
are changed to emphasize that their objectives are to ensure stakeholder commitment
to proceed to the next level of resource expenditure based on a thorough feasibility and risk analysis, and not just on the existence of a set of system objectives and a set of architecture diagrams. Thus, the RUP Life-Cycle Objectives (LCO) milestone is called the Architecture Commitment Review (ACR) in the ICM, and the RUP Life-Cycle Architecture (LCA) milestone is called the Development Commitment Review (DCR).

In comparison to the sequential waterfall and V-model, the ICM explicitly does the following:
• Emphasizes concurrent engineering of requirements and solutions.
• Establishes feasibility rationales as pass/ fail milestone criteria.
• Enables risk-driven avoidance of unnecessary documents, phases, and reviews.
• Provides support for a stabilized current-increment development concurrently with a separate change processing and rebaselining activity to prepare for appropriate and stabilized development of the next increment.