Sub-project is a small project within the framework of a larger project. It includes a planned series of interrelated tasks to be performed over a fixed period of time and within certain cost, effort and other limitations. Sub-projects serve as structural elements for broader projects and usually obtain middle and high levels in project hierarchies.
Sub-projects (aka "child projects") are integral components of parent projects. They may belong to project portfolios or programmes. Essentially, a sub-project does not differ from a project; the only differences are:
- A sub-project is dependent on other sub-projects belonging to the same project environment
- A sub-project is substantiated to a high-level (parent or portfolio) project or programme
The idea behind using sub-projects in a project environment can be explained by these items:
- There is a larger project that is hard to manage, so decomposing it into sub-projects makes the management process much easier and understandable
- There are several sponsors involved in one and the same project or program, and decomposing this project/program into several sub-projects allows the sponsors to efficiently share their impact and governance within the environment.