OpenUP is a lean Unified Process that applies iterative and incremental approaches within a structured lifecycle. OpenUP embraces a pragmatic, agile philosophy that focuses on the collaborative nature of software development. It is a tools-agnostic, low-ceremony process that can be extended to address a broad variety of project types.

However, OpenUP misses defining the concepts of RACI and Entry/Exit criteria. RACI is recognized as a key requirement for meeting software development governance objectives. Entry/Exit criteria are well known process modeling concepts that are widely adopted across different methodologies and in standard specifications such as SPEM.  

Personal effort on an OpenUP project is organized in micro-increments. These represent short units of work that produce a steady, measurable pace of project progress (typically measured in hours or a few days). The process applies intensive collaboration as the system is incrementally developed by a committed, self-organized team. These micro-increments provide an extremely short feedback loop that drives adaptive decisions within each iteration.

OpenUP divides the project into iterations: planned, time-boxed intervals typically measured in weeks. Iterations focus the team on delivering incremental value to stakeholders in a predictable manner. The iteration plan defines what should be delivered within the iteration, and the result is a demo-able or shippable build. OpenUP teams self-organize around how to accomplish iteration objectives and commit to delivering the results. They do that by defining and "pulling" fine-grained tasks from a work items list.