What is business process modeling and notation (BPMN)?

Originally developed by the Business Process Management Initiative (BPMI), BPMN is a precise, graphical notation for documenting business processes. It resolves the ambiguities of textual process specifications by visually depicting the sequence of business activities and information flows needed to complete a specific process. In recent years, BPMN is increasingly referred to as business process model and notation.

The Object Management Group (OMG) has maintained BPMN since 2005. This open consortium helps ensure that business process diagrams can be easily exchanged in a standardized format across different modeling tools. The goal of process modeling notation is to help organizations model ways to improve efficiency, account for new circumstances or gain a competitive advantage.

BPMN 2.0 is part of the OMG “triple crown” of process improvement standards, which also includes case management model notation (CMMN) and decision model notation (DMN). The standards differ from the unified modeling language (UML) used in software design. OMG’s BPMN 2.0.1 specification has been published as International Standard ISO/IEC 19510:2013.

BPMN provides a common business process modeling language that’s readily understandable by all business stakeholders—the business process analysts who create and refine processes, the technical developers responsible for implementing business processes and the business users who monitor and manage them. All three are key stakeholders in optimizing business operations.

The BPMN specification is designed to help organizations:

• Reach faster agreement on current and future processes through unambiguous models.

• Encourage stakeholder participation through graphically expressive notations.

• Facilitate the analysis and improvement of operations through business process reengineering.

• Create a library of process flows, case definitions and business rules to train new employees.

• Close communication gaps with a common language between business analysts, developers and other stakeholders.

• Inform business process automation efforts.

• Coordinate business process outsourcing strategies.

In addition, BPMN diagrams help teams create the Extensible Markup Language (XML) documents needed to run various processes, such as contract approvals or reminders for monthly financial reports. A related XML standard is the Business Process Execution Language (BPEL) for web services.

The BPMN language is based on flowcharts and graphical notations. The standard notation used to represent BPMN elements is separated into several categories for diagramming:

Flow objects are descriptive objects that define a process, such as events, activities and gateways.

Events are triggers that start, alter or conclude a process. Start events initiate a process, intermediate events occur during a process and end events conclude a process. Events can include messages, timers and dates, transactions, errors, escalations, requests and more.

BPMN depicts events as circles containing symbols specific to the event type. Throwing events initiate a process, while catching events occur as a result of a throwing event.

Activities are actions or tasks performed during the business process. The process mapping procedure shows all the activities that must occur as a response to start events and as prerequisites for end events. As more business processes undergo automation, many events trigger on their own. Activities can be simple or more complex, including subprocesses and multiple iterations. Business process diagrams show activities as rounded rectangles.

Gateways are decision points requiring an active choice to be made before progressing further through the business process. Shown as diamonds, gateways lead to at least two possible outcomes depending on the decision made.

• Exclusive gateways forward the workflow down one of several mutually exclusive pathways—the workflow must proceed down only one of the available options. They are depicted as diamonds containing an X.

• Inclusive gateways also offer multiple paths forward, but the options are not mutually exclusive. They are shown as diamonds containing a circle.

• Parallel gateways break a process into multiple flows without requiring a decision. The workflow simply splits into multiple simultaneous processes, which are shown as diamonds containing a plus sign.

• Parallel event-based gateways split a workflow into multiple concurrent pathways as the outcome of a triggering event. The symbol for parallel event-based gateways combines that of inclusive and parallel gateways with a diamond containing a plus sign enclosed in a circle.

• Complex gateways are reserved for highly complex processes. They are depicted as diamonds containing an asterisk.

Connecting objects are shown as lines with arrows and are used to connect flow objects.

• Sequence flows link activities in the order that they are performed within the business process. They are drawn as solid lines with arrows indicating the order of events. Default flows are the standard response to a triggering event, while conditional flows occur instead when a specified condition is met.

• Message flows are communications that flow between pools—discrete departments or other groups. They are depicted as dashed lines with a circle at the sender and an arrow at the receiver.

• Associations are dotted lines that link events, activities and gateways to supplemental information about those flow objects.

Swimlanes are containers that separate one set of activities from others. In BPMN standard notation, pools represent the major participants in a process. A different pool might be a different company, department or customer involved in the process. Lanes within a pool show the activities and flow for a certain role or participant, defining who is accountable for specific parts of a process.

Change management requires a thorough understanding of an organization's division of work, making swimlanes an essential feature of BPMN.

Artifacts provide supplemental information about the process, such as data objects, groups and annotations. A data object shows the data that is necessary for an activity and can represent either data input or data output. A group shows a logical grouping of activities, while an annotation gives details about what’s happening in a part of the diagram.

BPMN diagrams can be simple or complex and depict both internal and external processes. These are some of the types of diagrams:

• Collaboration diagrams show the interactions between two or more processes with multiple pools. They focus on the work performed by each pool, which can pass messages to each other.

• Choreography diagrams show the interactions between two or more participants. They can be contained within a collaboration, adding tasks and sequences that establish how the participants interact more fully.

• Conversation diagrams are simplified versions of collaboration diagrams. They show a group of related message exchanges in a business process.