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Parallel Approval with Threshold

Send approval requests to multiple people simultaneously and proceed when a minimum number approve. Faster than serial chains for peer-level decisions.

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BPMN 2.0
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Visual Flow

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When to Use This Pattern

Use parallel approval when:

  • Multiple peer-level reviewers need to weigh in (e.g., 3 board members)
  • You need consensus but not unanimity — "2 out of 3 must approve"
  • Speed matters more than sequential sign-off
  • The approvers don't depend on each other's decisions

How It Works

All approvers receive the request at the same time. The workflow tracks responses and proceeds once the threshold is met.

ConfigurationBehavior
All must approveWait for every approver. Any rejection = rejected.
Majority rulesWait for >50% to approve. If majority reject, rejected.
First response winsThe first approver's decision is final. Others are cancelled.
N of MRequire exactly N approvals out of M approvers (e.g., 2 of 5).

Implementation Guide

Step 1: Define the Approver Pool

Determine who participates. Sources:

  • SharePoint group membership
  • Database lookup (project stakeholders table)
  • A multi-person field on the request form
  • AD group members
Step 2: Set the Threshold Rule

Decide the completion criteria:

threshold = 2          // minimum approvals needed
total_approvers = 3    // total people asked
timeout_days = 5       // max wait time
Step 3: Fan Out the Tasks

Create a task for each approver simultaneously. Each task should include:

  • The full request details
  • A note about the threshold ("2 of 3 approvers must agree")
  • Approve / Reject actions
Step 4: Track and Evaluate

As responses come in, evaluate the threshold:

Scenario (2-of-3 threshold)ApprovedRejectedPendingResult
First response: Approve102Continue waiting
Second response: Approve201Approved — cancel pending tasks
Second response: Reject111Continue waiting
All responded120Rejected
Step 5: Clean Up

When the threshold is met:

  • Cancel remaining tasks so approvers don't get confused by stale requests
  • Notify everyone of the outcome, including who approved/rejected
  • Log the full voting record for audit

Tips & Best Practices

Warning

If approvers can see each other's votes, you introduce bias. Consider hiding intermediate results until the threshold is met, especially for sensitive decisions.

  • Handle ties explicitly. If you use majority rules with an even number of approvers, define what happens on a 50/50 split.
  • Set a timeout. Use the Escalation with SLA Timeout pattern for non-responsive approvers.
  • Weight the votes for advanced scenarios — a senior stakeholder's approval could count as 2 votes.
  • Combine with serial. A common pattern: parallel approval from peers → then serial approval from a final authority.

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