Comprehensive Guide to Case Management Model and Notation (CMMN) in BPMN

Introduction to CMMN and Its Role in BPMN

Case Management Model and Notation (CMMN) is a declarative modeling language designed for unpredictable, knowledge-intensive processes where activities are dynamically adapted based on evolving circumstances. Unlike BPMN (Business Process Model and Notation), which focuses on structured, predefined workflows, CMMN empowers knowledge workers to make decisions at runtime, emphasizing flexibility over rigid sequences.

Key Differences Between BPMN and CMMN

BPMN	CMMN
Imperative (prescribes exact steps)	Declarative (specifies outcomes, not paths)
Process-centric (fixed sequences)	Data-centric (driven by case file data)
Models “how” tasks are performed	Focuses on “what” needs to be achieved
Suited for repetitive, predictable workflows	Ideal for ad-hoc, case-driven processes (e.g., insurance claims, patient care)

CMMN complements BPMN, enabling organizations to model both structured and unstructured workflows within a unified framework.

Core Components of CMMN

a. Case Plan Model

A case plan defines the initial structure of a case, including mandatory and discretionary tasks. It includes:

• Tasks: Units of work (e.g., Human Tasks, Process Tasks, Case Tasks).
• Discretionary Tasks: Optional tasks added by knowledge workers during runtime.
• Stages: Logical groupings of tasks (e.g., “Complaint Handling” in a customer service case).

b. Case File

A central repository for all case-related data (e.g., documents, decisions, event logs). Case workers modify this dynamically.

c. Events and Milestones

• Events (e.g., Timer Events, User Events): Trigger actions based on time or user input.
• Milestones: Represent achievable targets (e.g., “Payment Verified”).

d. Sentries (Entry/Exit Criteria)

Conditions or events that determine when a task/stage becomes active or terminates. For example, a payment task might activate only if the case file contains a valid invoice.

How CMMN Integrates with BPMN

CMMN and BPMN are complementary:

1. Structured vs. Unstructured Workflows:
   • Use BPMN for repeatable processes (e.g., order processing).
   • Use CMMN for dynamic scenarios (e.g., resolving customer complaints).
2. Hybrid Modeling:
   • Link CMMN tasks to BPMN subprocesses. For example, a “Process Payment” task in CMMN could trigger a BPMN payment workflow.

Example: A customer complaint case (CMMN) might include a structured refund process (BPMN) as one of its tasks.

Visual Paradigm’s Support for CMMN and BPMN

Visual Paradigm is a robust tool that supports both BPMN and CMMN, enabling seamless integration of structured and case-driven workflows.

Key Features

1. CMMN Diagram Tools:
   • Intuitive drag-and-drop editor for designing case plans, stages, and discretionary tasks.
   • Link CMMN tasks to BPMN processes for hybrid modeling.
   • Export diagrams in PNG, PDF, SVG, and JPG formats.
2. BPMN 2.0 Support:
   • Model subprocesses, events, and gateways with syntax validation.
   • Generate RACI and CRUD charts directly from BPMN diagrams.
3. Simulation and Animation:
   • Animate workflows to visualize process execution and identify bottlenecks.
   • Simulate resource consumption (e.g., time, cost) for both BPMN and CMMN models.
4. Collaboration and Documentation:
   • Real-time collaboration with commenting and task management.
   • Generate detailed reports integrating BPMN and CMMN artifacts.

Example Workflow in Visual Paradigm

1. Design a CMMN case plan for “Insurance Claim Handling,” including discretionary tasks like “Request Additional Documentation.”
2. Link the “Approve Claim” task to a BPMN approval workflow.
3. Simulate the case to evaluate processing times and resource allocation.

Case Study: Writing a Document

The provided diagram illustrates a case management process for writing a document using CMMN. Let’s break down the diagram and explain each element:

Case

The entire diagram represents a case for writing a document.

Stages

• Prepare Draft: This stage includes tasks and events related to preparing the initial draft of the document.
• Review Draft: This stage includes tasks and events related to reviewing the draft.

Tasks

• Write Text: A manual task where the case worker writes the text for the document.
• Create TOC (Table of Contents): A task to create the table of contents for the document.
• Organize References: A task to organize the references used in the document.
• Generate List of Figures: A task to generate a list of figures used in the document.
• Integrate Graphics: A task to integrate graphics into the document.
• Accept/Reject Comments: A task to accept or reject comments received during the review process.
• Verify Grammar and Spelling: A task to verify the grammar and spelling of the document.

Events

• Start Event: The start event triggers the beginning of the case.
• Intermediate Events: These events occur during the case and can affect the flow of tasks. For example, the completion of the “Prepare Draft” stage triggers the “Draft Completed” event.
• End Event: The end event signifies the completion of the case.

Milestones

• Draft Completed: A milestone indicating the completion of the draft.
• Document Completed: A milestone indicating the completion of the entire document.

Sentries

Sentries are used to control the flow of tasks and stages. For example, the “Accept/Reject Comments” task is activated based on the sentry condition that checks for the presence of comments.

Step-by-Step Explanation

1. Initiation:
   • The case starts with the “Write Document” event, triggering the “Prepare Draft” stage.
2. Prepare Draft:
   • Write Text: The case worker starts by writing the text for the document.
   • Create TOC: Simultaneously or sequentially, the case worker creates the table of contents.
   • Organize References: The case worker organizes the references used in the document.
   • Generate List of Figures: The case worker generates a list of figures used in the document.
   • Integrate Graphics: The case worker integrates graphics into the document.
   • Once all these tasks are completed, the “Draft Completed” milestone is achieved, triggering the “Draft Completed” event.
3. Review Draft:
   • Seek Comments: The draft is sent for review, and comments are sought from reviewers.
   • Accept/Reject Comments: The case worker reviews the comments and decides whether to accept or reject them.
   • Verify Grammar and Spelling: The case worker verifies the grammar and spelling of the document.
   • Once the review is completed, the “Document Completed” milestone is achieved, triggering the “Document Completed” event and ending the case.

Benefits of Using CMMN

1. Flexibility: CMMN allows for flexible and dynamic case management, making it suitable for unpredictable and knowledge-intensive processes.
2. Collaboration: CMMN supports collaborative work environments where multiple case workers can contribute to different parts of the case.
3. Adaptability: CMMN can adapt to changing circumstances and decisions made by case workers, ensuring that the case progresses smoothly.
4. Visibility: CMMN provides a clear visual representation of the case, making it easier for stakeholders to understand the structure and flow of the case.

Best Practices for Using CMMN with BPMN

1. Define Clear Boundaries: Use BPMN for predictable steps and CMMN for dynamic decision-making.
2. Leverage Case Files: Ensure all stakeholders access real-time case data to enable informed decisions.
3. Iterate with Stakeholders: Validate models using Visual Paradigm’s collaboration tools.
4. Combine with DMN: Use Decision Model and Notation (DMN) to formalize business rules within CMMN cases.

Conclusion

Visual Paradigm fully supports CMMN and BPMN integration, offering tools to model, simulate, and refine both structured and ad-hoc workflows. By combining these standards, organizations can address a broader spectrum of business processes, from routine tasks to complex case management.

Next Steps

• Explore DMN for decision logic in CMMN cases.
• Utilize Visual Paradigm’s animation tools to communicate workflows to stakeholders.

For implementation details, refer to Visual Paradigm’s CMMN documentation.