How to Use a Text-Based Data Flow Diagram in Your Business Analysis Report

Although the data flow diagram is a graphic, as the name suggests, you can also use a text-based version called the external interaction textual template.

You use these techniques to analyze and communicate. If text communicates better to your stakeholders, use the textual template rather than the diagram.

Introduction to data flow diagrams for business analysis

• Circles: The circles represent the process (or the function) that actually works to transform inputs into outputs. In the example below, the process involves taking in all the information from the guest (input) and sending it off to the reservation system (output).

• Curved lines: The curved lines represent the data flowing into and out of the process. These bits of data aren’t detailed data elements but rather a conglomeration of data called net flow. In the example, dates coming from the guest into the process are arrival and departure dates (including times), but instead of getting that detailed, the diagram simply summarizes them as “dates.”

• Rectangular boxes: The rectangular boxes represent external agents that are sources or recipients of data. Your project has no control over how these sources execute their internal processes (their work), and the project can only send data to and receive it from them.

  For example, you have no idea how the reservation system processes its data, but based on what you send the system, you get the availability and price information from it.

  

  Credit: Illustration by Wiley, Composition Services Graphics

• When identifying stakeholders (those external agents!)

• When scoping your project and figuring out your boundaries

The disadvantages primarily have to do with reader understanding:

• The diagram doesn’t show sequence, so some businesspeople may have a hard time following it.

• The diagram presents the data flowing into and out of the project at a rather high level. It doesn’t show all the data elements, which may be problematic for detail-oriented folks.

• The data flow has kind of fallen out of favor because, outside the scope diagram, businesspeople don’t relate to the many levels of the data flow diagram. They prefer a workflow.

1. Identify the process you’re documenting (the circle in the middle of the diagram).

2. Identify all the parties and systems (the rectangles) involved in the process.

3. Elicit from the stakeholders the data (the curved lines) flowing among the parties, the systems, and the process.

4. Have the stakeholders validate your diagram.

The external interaction textual template for business analysis

You can see that the left-hand column lists the external agents (the rectangles on the data flow diagram), and the middle and right-hand columns list the data itself (the curved lines on the diagram).

Credit: Illustration by Wiley, Composition Services Graphics