Processes are one of the four Components of PIRRIDM. This article:

  • Provides a definition of Process.
  • Identifies broad categories of Processes.
  • Identifies the constituent parts of a Process.

There are a number of definitions of a Process, but I have chosen to adapt a definition of a Use Case in UML 2.5.1.

A Process describes a behaviour within a business. A Process describes how one or more specific persons or systems, all of which are described in Information, completes Activities or Tasks to accomplish a goal that is of value to the business. 

I have found it useful to divide processes into two broad categories:

  • Business Processes, which describe processes from the perspective of the people, tasks, activities, and information that are required to complete one or more business objectives, and
  • System Processes, which describe processes from the perspective of the people, systems, programs, user interfaces, APIs, networks, and data that are required to implement one or more Business Processes.

Constituent Parts of a Process

Regardless of whether we are looking at a Business Process or a System Process, there are certain constituent parts that they share. Business Processes and System Processes will implement these parts differently, but the structure is the same.


Pre-Conditions are a set of facts that must all be true before a Process can be successfully started. These consist of Information that must be in a specific state. If there are a large number of Pre-Conditions, I have found it useful to group these into sets of Pre-Conditions. This allows the ability to use the same set of Pre-Conditions to be applied to more than one Process and the ability to have multiple sets of Pre-Conditions to be used at the start of a Process.


A Trigger is a specific task or activity that initiates the Process. Every Process will start with a single trigger.

Tasks, Activities, and Results

The core of a process consists of the tasks and activities that are performed during the process and the results that occur as the result of performing the tasks or activities. Tasks are simple statements of a Person or System performing some action that is intended to affect one or more items of Data. Activities are a logical grouping of tasks that are grouped because of the number of tasks required to achieve one or more specific results. Results describe the impact of performing the task or activity on the Data.


Post-Conditions are a set of facts, of which at least one must be true, at the conclusion of a Process. I have found it useful to group Post-Conditions into sets. Within each set, all of the Post-Conditions must be true. This is useful to identify the Post-Conditions that are true when a Process is successfully executed or if there is an alternative set of Post-Conditions, such as would be the case if an error was encountered during a Process or if the Process results in a different, but still acceptable set of Post-Conditions.