Process activity is a set of operations or tasks executed by a person or entity, which belongs to a particular process. Defines the smallest measurable amount of work that must be performed to convert a portion of the process inputs to the desired outputs. All activities included in the same process create a definition of the work that the process performs.

Each activity in a process has some characteristics that define its class and nature. These features are:

  1. Measurable duration.
  2. Logical relationship with other activities in the same process.
  3. Resources that are consumed as the activity changes state.
  4. Costs that define the amount of money required to perform the activity.
  5. Role that executes the activity.
  6. Data it consumes and data it produces.

In the process modeling phase, each of its activities is analyzed to define and measure each of these characteristics.