Why this matters
Validating BPMN diagrams with Subject Matter Experts (SMEs) ensures your process maps reflect the real world—not just assumptions. In a Business Analyst role, accurate validation reduces rework, clarifies responsibilities, and surfaces hidden rules and exceptions before changes are implemented.
- Reduce costly misinterpretations of handoffs between teams.
- Uncover edge cases, waiting states, and timers that impact SLAs.
- Confirm decision rules, triggers, data inputs/outputs, and swimlane ownership.
Concept explained simply
SME validation is a focused review of a draft BPMN process with people who do the work. You bring a best-effort diagram and ask SMEs to confirm or correct it.
Mental model: Map vs. Territory
Your BPMN is a map. SMEs live in the territory. Validation aligns the map to the territory by checking triggers, paths, decisions, data, and ownership. The goal is not to brainstorm a brand-new process—it's to confirm what exists (or agree on a to-be version with explicit decisions and assumptions).
- Validation is about accuracy and completeness, not eliciting from scratch.
- Drive specifics: events, gateways, exceptions, data artifacts, timers, and message flows.
When to validate & who to invite
- Timing: After initial elicitation and first draft; repeat after major changes.
- SMEs: 4–8 people across roles (operators, approvers, compliance/risk, IT/system owners, QA/support, data/reporting).
- Format: 60–90 minutes live session; asynchronous comments if needed.
Preparation checklist
- Draft BPMN (clear lane names, events, gateways labeled).
- Assumptions list and open questions.
- Glossary of terms and abbreviations used in the diagram.
- Known variants (e.g., premium clients, regional exceptions).
- Decision log (new items to be added during session).
- Clear objective: validate current state, or confirm to-be proposal.
Running the session (60–90 min agenda)
- Frame (5 min): Goal, scope, what sign-off means, how feedback will be captured.
- Walk-through (15–25 min): Read left-to-right: start event, lanes, happy path, then decisions and exceptions.
- Deep-dive (20–40 min): Clarify decisions, timers, message flows, data inputs/outputs, and systems touched.
- Converge (10–15 min): Confirm open issues, owners, due dates, and sign-off criteria.
- Close (5 min): Next steps and timeline to share the updated version.
Guided questions to use
- Trigger: What event starts this process? Is it manual, message, timer, or signal?
- Ownership: Which lane owns each task? Any RACI confusion?
- Decisions: What rules lead to each gateway outcome? Are outcomes mutually exclusive?
- Waiting states: Do we wait for a response? How long? What happens on timeout?
- Handoffs: Are these message flows across pools, not sequence flows?
- Data: What inputs are required to start/finish tasks? What documents are produced?
- Exceptions: What can go wrong? How is it handled? Error vs. escalation vs. alternate path?
- KPIs/SLAs: Where are they measured? What events mark start/stop?
Worked examples
Example 1: Retail loan application (as-is)
Issue: Draft had a single flow from underwriting to offer with no handling of missing documents.
- Fix: Add a user task "Request documents" with a timer boundary event (5 business days) leading to a reminder and eventual cancellation.
- Decision: After "Underwrite loan", use an exclusive gateway with outcomes Approve/Reject; label outgoing flows with rule summaries.
- Communication: Create separate pools for Bank and Customer. Use message flows from "Send offer" to Customer and from Customer "Accept offer" back to Bank.
Example 2: IT incident triage
Issue: Sequence flow crossed a vendor boundary and error handling was unclear.
- Fix: Use message flow to notify Vendor pool, not sequence flow across pools.
- Parallel actions: Use a parallel gateway to both log the ticket and alert on-call.
- Errors: Add an error boundary event on "Run fix script" that routes to rollback and escalation.
Example 3: Procurement approval (to-be)
Issue: Draft mixed amount-based and category-based approvals in one gateway.
- Fix: Use an inclusive gateway to allow multiple approvals when both amount and category rules apply.
- Data clarity: Add data objects "PO Request" and "Approval Memo" with associations to tasks.
- Role clarity: Convert generic tasks to user tasks under Finance/Procurement lanes; ensure each task has a clear owner.
Quality criteria for a validated BPMN diagram
- Each pool has at least one start and one end event; no orphaned flows.
- No sequence flows cross pool boundaries; cross-organization communication uses message flows.
- Gateways have clear conditions; labels on outgoing paths are unambiguous.
- Wait states use events (timer/message); timeouts are explicit.
- Lanes reflect responsibility; no task without an owner.
- Data inputs/outputs and key documents are shown where relevant.
- Known exceptions have explicit handling paths.
- Unresolved items documented in the decision log with owners and due dates.
Exercises
Do these right after reading. They mirror the practice section below and help you prepare for the Quick Test. Everyone can take the test; only logged-in users will have progress saved.
Exercise 1: Validate the loan approval BPMN draft (matches Exercise ex1)
You’re given a textual draft: In one pool (Bank), a message start event triggers "Check completeness" then "Underwrite loan". After that, the flow goes to "Send offer" and ends. If incomplete, the analyst emails the customer and waits. If rejected, the analyst tells the customer. The customer replies by email. Sequence flows cross into the customer’s tasks.
- Identify at least 6 issues and propose BPMN corrections.
- Specify event types (message/timer), gateways (exclusive/inclusive/parallel), pools/lanes, and data objects.
- Define what happens on no response within 7 days.
Show one possible solution
- Two pools: Customer and Bank; no sequence flow across pools, use message flows for communications.
- Bank pool starts with a message start (application received) and ends with either Offer Accepted (end) or Rejection Notified (end).
- After "Check completeness": exclusive gateway Complete?/Incomplete. If Incomplete: user task "Request documents" to Customer with a timer boundary (7 days) to send reminder and then cancel application.
- After "Underwrite loan": exclusive gateway Approve/Reject. If Reject: task "Notify rejection" then end.
- If Approve: task "Send offer" (Bank) -> message flow to Customer. Use an event-based gateway to wait for either message catch "Customer accepts" or timer (7 days) leading to expire/close.
- Add data objects: "Application package" input to underwriting; "Offer letter" produced by Send offer.
- Checklist: Are start/end events explicit? Are all cross-organization interactions shown as message flows? Are wait states modeled with events? Are decision outcomes labeled?
Common mistakes & how to self-check
- Skipping message flows: If different organizations are involved, look for sequence flows crossing pools—replace with message flows.
- Unlabeled gateways: If a path seems ambiguous, label conditions on outgoing edges.
- Hidden timers: Any SLA or wait? Model as timer events instead of vague tasks like "Wait".
- Ownerless tasks: Every task belongs to a lane with a clear responsible role.
- No exception path: If something can fail, add an error/escalation path or an alternate route.
Self-check mini list
- Can you point to the trigger, the happy path, and each exception?
- Can an outsider identify who does each task without asking?
- Could a developer or operations lead implement changes using only this diagram and decision log?
Practical projects
- Map and validate a current small process (e.g., employee equipment request) with 3–5 SMEs; capture 5+ corrections and a signed-off version.
- Take a to-be process proposal (e.g., adding an approval step) and run a validation session to confirm decisions, timers, and handoffs.
Communication templates
Invite email (copy/paste)
Subject: BPMN process validation — 60–90 min session
Hi all,
We’ll review the attached BPMN draft to confirm accuracy (current state) and capture any corrections. Goal: agree on decisions, exceptions, roles, and handoffs. Please skim the diagram, assumptions, and open questions before the meeting. Bring any edge cases.
Outcomes: updated diagram, decision log entries, and sign-off criteria.
Thanks!
Sign-off statement
We confirm this diagram reflects the process as understood on [date], with open items tracked in the decision log (#) assigned to owners with due dates.
Mini challenge
Pick any diagram you have. In 10 minutes, mark with sticky notes or comments:
- One missing message flow
- One missing timer or event-based wait
- One unlabeled decision outcome
- One task with unclear ownership
Who this is for
- Business Analysts mapping current or to-be processes.
- Team leads and product owners who need clear handoffs across teams/vendors.
Prerequisites
- Basic BPMN notation: events, tasks, gateways, pools/lanes, message vs. sequence flows.
- Initial process draft ready for review.
Learning path
- Refresh BPMN basics (events, gateways, lanes).
- Draft a current-state map from interviews/documents.
- Run SME validation as described here; maintain a decision log.
- Incorporate changes; re-validate key exceptions.
- Prepare sign-off and share final diagram.
Next steps
- Complete the exercise above and compare with the solution.
- Take the Quick Test below to check your understanding. Everyone can take it for free; sign in if you want your score saved.