A Work Product is an abstract concept which provides a generalization for the concrete work product types Artifact, Outcome, and Deliverable. Work Product descriptions actually represents work product types, i.e. an instance of Work Product is a description of a specific type of work product and not an individual work product instance.  However, for simplicity reasons and because of low risk of misinterpretation we did not append the word 'type' to every element in UMA.

A Work Product is an abstraction for descriptions of content elements that are used to define anything used, produced, or modified by a task.  Roles use Work Products to perform Tasks and produce Work Products in the course of performing Tasks.  Work Products are the responsibility of a single Role, making responsibility easy to identify and understand, and promoting the idea that every piece of information produced in the method requires the appropriate set of skills. Even though one Role might "own" a specific type of Work Products, other Roles can still use the Work Products; perhaps even update them if the Role has been given permission to do so.

Popular Work Products in Software Development, and the approximate dependency relationships between them.

Note that Work Product is the term used to describe what other processes denote using terms such as Artifact, work unit, and so on. In UMA, Deliverables are only considered to be the subsets of all Work Products that will end up being delivered into the hands of the customers and users, usually as part of a formal or contractually agreed hand-over.