What is a flow diagram & flowchart? (7 types + definitions)
They're time-savers. They're explainers. They're clarity makers. Diagramming helps you create efficiency and optimize business processes (and more!) and a simple flowchart can go a long way towards improving workflow. Those are the benefits, but let's circle back to the headline; what is a flow diagram and what is a flowchart? At the most basic level, they're charts that describe a procedure, one step at a time.
What is a flow diagram? Our definition
A flow diagram is a visualization of a sequence of actions, movements within a system and/or decision points. They’re a detailed explanation of each step in a process, no matter the level of complexity of that process. Flow diagrams, also known as flowcharts, are powerful tools for optimizing the paths - or flow - of people, objects or information through a system or procedure. The connectors and symbols work together to create a visual representation of the direction of movement and what’s needed to make that movement happen.
Types of flow diagrams and flowcharts + uses & examples
The uses of flow diagrams are vast and honestly endless. If something requires multiple steps, a graphical representation can be made to visualize each of those steps with a diagram creator.
Before you jump into how to make a flowchart though, it’s important to understand the various types of flowcharts because some are better suited to meet certain goals than others. So let’s break down which flow diagram you’d want to use for which circumstance.
And if you're not sure where to start, let our diagram templates guide the way.
1. Data flow diagram (DFD)
This type of diagram is used to map the flow of data or through an information system or process. A DFD would therefore also show all the accompanying inputs, outputs and functions that relate to the capture or use of data as well where the data lives.
Data flow diagrams are perhaps the most specialized of the flow chart/diagram family and actually have their own type of notation and flowchart symbols: Yourdon & Coad and Gane & Sarson. Both duos wrote seminal books that included DFDs, “Structured Design” by the former, “Structured Systems Analysis: Tools and Techniques” by the latter.
Data flow diagrams can be further broken down into Logical DFDs and Physical DFDs. Logical diagrams focus on the business operations in relation to data and information flow, not how the system itself works. They're less technical and therefore easier to understand. Physical DFDs go into a deeper level of details; the who, what and where of data flow.
What are data flow diagrams used for?
These are most commonly used in software engineering, development and computer programs, which is where they arose from. They're also useful for managing and trimming the fat from business processes and logistics.
2. Workflow diagram
If the idea is to work smart, not harder, putting together a workflow diagram is something you should consider. These diagrams can be created at the organization level all the way down to charts for a particular service or a single project to chart the flow of decisions, documents, tasks and activities.
Where a user flow diagram optimizes how a user interacts with your product or service, a workflow diagram ensures optimization of your internal processes.
What are workflow diagrams used for?
They're largely used for improving how work gets done and identifying bottlenecks you may have missed. These can also be helpful for onboarding new employees so they know exactly where they fit in the flow.
3. Swimlane flowchart
How do you keep track of who does what and when in an interdisciplinary or collaborative project? The difference between a swimlane diagram and the workflow diagram is that each person, group, department, etc. of a process has a clear cut lane. Whichever way you orient the lanes, vertically or horizontally, the point is to see the entire process and the interactions between the various role players as they happen in a neat and easily consumable way.
Think of this as almost an “interaction flowchart”.
What are swimlane flowcharts used for?
These are used when you have a cross-team project that requires a lot of interaction between various departments or employees. This is also a great tool for pinpointing and fixing inefficiencies in the course of getting the job done.
4. Process flow diagram (PFD)
Process flow diagrams, or process maps, come to us from the world of mechanical engineering. Specifically from Frank and Lillian Gilbreth, industrial engineers who wrote about the concept all the way back in 1921 in “Process Charts: First Steps in Finding the One Best Way to Do Work”.
As they put it, “the process chart is a device for visualizing a process as a means of improving it. Every detail of a process is more or less affected by every other detail; therefore the entire process must be presented in such form that it can be visualized all at once before any changes are made in any of its subdivisions”.
In other words, a PFD sequentially depicts the steps of a process and its sub-processes and how they relate to one another.
While a process flow diagram, or process flowchart, is still often used in engineering you can use it for any application, in any industry.
What are process flow diagrams used for?
Given the origins, process flow diagrams are useful in standardizing processes, improving existing processes and developing altogether new ones.
These are also helpful for quality control in the scope of a process.
5. Event-driven process chain (EPC)
EPCs, or event-driven process chains, are flowcharts that are specifically meant for illustrating and modeling business processes as a chain of events and activities that influence each other.
This type of chart also has some of its own unique notation, notably the AND, OR and XOR operators along some of the connectors depending on the process.
What are event-driven process diagrams used for?
This ordered graph is commonly used for revamping business processes, resource planning as well as modeling and analysis of business operations.
6. Specification and description language diagram (SDL)
SDL diagrams are for detailing the specific behavior of real-time systems, with said system broken down into blocks and processes. Given the name, these diagrams lay out the specifications and states of behaviors throughout a system.
What are specification and description language diagrams used for?
These are most often used in industries like telecoms, aviation and medicine to describe state machines.
7. Unified modeling language diagram (UML)
Unified modeling language diagrams, or UMLs, are quite similar to SDLs and illustrate a system and how users interact with it, generally software, from a higher level.
The most common of these are activity diagrams and are used to illustrate the actions in a process.
What are unified modeling language diagrams used for?
You're going to find UML diagrams to be most useful in software development and engineering.
Get some helpful information on designing flow diagrams with Slickplan including features, strategies, tips, tools, and more.