# Decision Model and Notation

**In short:** DMN is a standard for modeling business decisions. It pairs a graphical notation with an expression language, so business users can read decisions and a decision engine can run them alongside a BPMN process.

## Explanation

Decision Model and Notation (DMN) is owned by the OMG, a standards body. It gives you two tools for modeling decisions: a graphical notation and an expression language. Its primary goal is a common notation that all business users can understand.

**Decisions apart from process flow**

DMN is designed to work alongside BPMN, the standard notation for business processes. See BPMN 2.0 Notation for that language. A BPMN business rule task models the evaluation of a business rule. When a process instance reaches such a task, a decision engine evaluates a DMN decision. The process only says when to decide. The decision logic lives in the DMN model. This is how decision logic stays separate from process flow.

**Two views of a decision**

- **Decision Requirements Diagram (DRD).** Modeling starts in this view. It is the graphical part of DMN.
- **Decision table.** This is decision logic shown as a table. It has inputs, outputs and rules. DMN includes decision tables as a built-in feature.

**Expressions**

DMN also has an expression language, called FEEL. A business knowledge model (BKM) can hold a literal expression. That expression can take parameters, which serve as inputs to the FEEL expression.

## Example

An online shop wants to decide whether an order needs a manual check. The order process reaches a business rule task named "Check order risk". The decision engine evaluates a decision table. Its inputs are order amount and customer history. Its output is "manual check" or "auto-approve". The process then continues along the matching path. A business user can read the table rows without reading the process logic.

BPMN diagram: [A process calls a DMN decision through a business rule task, then routes on the result.](https://arc.fuet.ch/diagrams/concepts/modeling-bpmn/decision-model-and-notation/diagram-1.bpmn)

## Checks

- Decision logic sits in a DMN model, not inside the process flow; the process calls it through a business rule task.
- Decision tables list their inputs, outputs and rules.
- Modeling of decisions starts from a Decision Requirements Diagram.

## Related

- [BPMN 2.0 Notation](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-2-0-notation-overview.md)
- [BPMN Activity](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-activity.md)
- [BPMN Task Marker and Task Type](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-task-marker.md)
- [BPMN Core Elements](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-core-elements.md)
- [BPMN Motivation](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-motivation.md)

## Sources

- [About the Decision Model and Notation Specification Version 1.7 beta](https://www.omg.org/spec/DMN) — omg.org, accessed 2026-11-09
- [About the Decision Model and Notation Specification Version 1.4](https://www.omg.org/spec/DMN/1.4/About-DMN) — omg.org, accessed 2026-11-09
- [Business rule tasks | Camunda 8 Docs](https://docs.camunda.io/docs/components/modeler/bpmn/business-rule-tasks/) — docs.camunda.io, accessed 2026-11-09
- [Overview | Camunda 8 Docs](https://docs.camunda.io/docs/components/modeler/dmn/decision-table/) — docs.camunda.io, accessed 2026-11-09
- [Modeling with DMN | Camunda 8 Docs](https://docs.camunda.io/docs/components/modeler/dmn/) — docs.camunda.io, accessed 2026-11-09