Business Sub-Process Modeling

In the previous chapter, we introduced sub-processes as meaningful parts of a larger business process. In this chapter, we look at how sub-processes can be modeled in a clear and practical way.

To do this, we use a well-known modeling concept called a use case. In our context, a use case is simply a way to describe a single sub-process from start to finish.

Use Case

A use case represents one sub-process and describes what happens when a specific role performs a specific piece of work.

The diagram below shows the receptionist’s business process represented as four use cases:

Each use case focuses on one responsibility:

• Patient identification
• Patient registration
• Appointment scheduling
• Visit finalization

Each of these use cases represents a single sub-process within the overall receptionist workflow.

Modeling a Sub-Process

A use case can be modeled using an activity diagram. This diagram shows how the sub-process starts, what activities are performed, and how it ends.

For example, the patient identification sub-process can be read as follows:

• The patient enters the dental office.
• The receptionist begins serving the next patient.
• The receptionist performs patient identification.
• The process ends when the patient is identified or not identified.

The diagram below visualizes this flow:

You can read any activity diagram in the same way: start at the initial state, follow the arrows, and observe how decisions lead to different results.

Simple and Complex Sub-Processes

Some sub-processes are very simple and always lead to the same result. Patient registration is an example of such a sub-process.

Other sub-processes involve decisions. Appointment scheduling depends on specialist availability and may lead to different outcomes.

These differences are clearly visible in activity diagrams, which makes them especially useful for discussing behavior with business stakeholders.

Use Case Elements

A use case uses the same basic elements we already know from sub-processes:

• Initial state
• Trigger
• Activities
• Rules and decisions
• Final states

Because of this, a use case can be seen as a visual definition of a sub-process.

Why Use Cases Are Useful

Use cases help us keep sub-processes clear and well-defined.

• They isolate responsibilities.
• They make behavior easy to discuss.
• They can be reused across different business processes.

In the next chapter, we will look more closely at diagrams that describe states and how they are connected.

Table of Content Introduction into Business Process Previous: Business Process Modeling Next: UML State Diagrams