Kanban Systems

Implement visual workflow management systems that optimize flow through WIP limits and continuous improvement.

Overview

Kanban is a workflow management method that visualizes work, limits work-in-progress, and optimizes flow for continuous delivery. Originating from Toyota's manufacturing system and adapted for knowledge work by David J. Anderson, Kanban provides a practical system for managing work with flexibility and efficiency. This skill covers Kanban principles, board design, WIP limits, flow optimization, and metrics.

Core Principles

1. Visualize the Workflow

Make invisible work visible using a Kanban board with columns representing workflow stages.

Basic Board Structure:

| Backlog | To Do | In Progress | Review | Done |

Advanced Elements:

• Swim lanes for work types (features, bugs, tech debt)
• Color coding by priority or class of service
• Blocked indicators
• Work item age
• Assignee avatars

2. Limit Work in Progress (WIP)

Restrict the number of items in each workflow stage to prevent overload and improve flow.

Setting WIP Limits:

• Initial: 1.5 × number of team members per stage
• Adjust based on observation and metrics
• Different limits for different stages
• Enforce strictly to drive improvement

Benefits:

• Faster completion of individual items
• Reduced multitasking
• Earlier identification of bottlenecks
• Improved focus and quality

3. Manage Flow

Ensure smooth, continuous movement of work through the system.

Flow Metrics:

• Lead Time: Request to delivery
• Cycle Time: Start to completion
• Throughput: Items completed per period
• Work Item Age: Time in system

Flow Optimization:

• Reduce batch sizes
• Minimize handoffs
• Balance capacity across stages
• Eliminate waste
• Address bottlenecks promptly

4. Make Policies Explicit

Document and share the rules governing the process.

Policies to Define:

• Definition of Ready for each column
• Definition of Done for each column
• Pull criteria (when to move work)
• Class of service policies
• Blocking and escalation procedures

5. Implement Feedback Loops

Regular meetings for inspection and adaptation.

Kanban Cadences:

• Daily Standup (15 min): Walk the board, identify blockers
• Replenishment Meeting (Weekly): Select new work from backlog
• Service Delivery Review (Monthly): Review metrics and customer satisfaction
• Operations Review (Monthly): Process improvements and capability development
• Retrospective (Bi-weekly/Monthly): Team reflection and improvement

6. Improve Collaboratively, Evolve Experimentally

Use scientific method for continuous improvement.

Improvement Process:

1. Observe problem or opportunity
2. Hypothesize potential improvement
3. Experiment with change
4. Measure impact
5. Decide: keep, modify, or discard
6. Repeat continuously

Kanban Board Design

Column Design

Typical Software Development Board:

Backlog → Analysis → Development → Code Review → Testing → Deployment → Done

Support/Maintenance Board:

Inbox → Triage → Investigation → Resolution → Verification → Closed

Marketing Board:

Ideas → Planning → Creation → Review → Approval → Publishing → Analysis

Swim Lanes

Horizontal rows for different work types or priorities:

• By Type: Features, Bugs, Technical Debt
• By Priority: Expedite, Standard, Intangible
• By Team: Team A, Team B, Shared
• By Project: Project X, Project Y, BAU

Card Information

Each work item card should include:

• Title and description
• Assignee(s)
• Priority/class of service
• Due date (if applicable)
• Blocked status and reason
• Age (days in system)
• Links to details

WIP Limits in Detail

Types of WIP Limits

Column Limits: Maximum items in entire column

| To Do (5) | In Progress (3) | Review (2) | Done |

Per-Person Limits: Maximum items per individual (1-2)

CONWIP: Constant WIP across entire board

Work Type Limits: Separate limits for bugs vs. features

Adjusting WIP Limits

Increase when:

• Frequent idle time
• Team members waiting for work
• High process efficiency (>80%)

Decrease when:

• Too much multitasking
• Items aging excessively
• Bottlenecks not visible
• Low process efficiency (<40%)

Handling WIP Limit Violations

• Make violations visible (different color, alert)
• Discuss in standup why limit exceeded
• Swarm to resolve before adding more work
• Track violation frequency as metric
• Adjust limits if consistently violated

Classes of Service

Differentiate work types with different risk profiles and urgency.

Visual Representation:

• Use swim lanes or color coding
• Red: Expedite
• Orange: Fixed Date
• Blue: Standard
• Green: Intangible

Identifying and Resolving Bottlenecks

Bottleneck Indicators

1. Card Accumulation: Column consistently at WIP limit
2. Increasing Cycle Time: Time in specific stage growing
3. CFD Widening: Cumulative Flow Diagram band expanding
4. Team Feedback: Complaints about waiting or overload
5. Aging Items: Cards stuck in same stage

Resolution Strategies

Clarify Exit Criteria: Ensure Definition of Done is clear

Redistribute Capacity: Move people to bottleneck stage, cross-train

Break Down Work: Split large items into smaller pieces

Address Dependencies: Identify and resolve external blockers

Adjust WIP Limits: Reduce upstream WIP to prevent overloading

Automate or Eliminate: Streamline repetitive tasks

Add Capacity: Hire or contract (last resort)

Kanban Metrics

Cumulative Flow Diagram (CFD)

Stacked area chart showing work items in each stage over time.

Healthy CFD:

• Smooth, parallel bands
• Consistent vertical distance (stable WIP)
• Steady upward slope (consistent throughput)

Problem Indicators:

• Widening band: Bottleneck
• Flat band: No work in stage
• Vertical jump: Batch arrival
• Narrowing band: Starvation

Lead Time Distribution

Histogram of lead times with percentiles.

Example:

• 50th percentile: 5 days
• 85th percentile: 10 days
• 95th percentile: 15 days

Commitment: "We'll deliver in 10 days with 85% confidence"

Throughput

Items completed per week/month.

Uses:

• Capacity planning
• Forecasting completion dates
• Identifying trends

Forecasting:

• Average throughput: 20 items/week
• Backlog: 100 items
• Forecast: 5 weeks (100 ÷ 20)
• Add buffer for confidence

Flow Efficiency

Percentage of time spent on value-adding work.

Formula: (Active time / Total lead time) × 100

Typical Knowledge Work: 15-20% Target: >40%

Kanban vs. Scrum

Scrumban

Combining Kanban and Scrum for best of both.

From Scrum:

• Sprint planning (or replenishment)
• Daily standup
• Retrospectives
• Optional roles

From Kanban:

• Visual board
• WIP limits
• Continuous flow
• Pull system
• Flow metrics

When to Use:

• Transitioning from Scrum to Kanban
• Need sprint structure with flow optimization
• Maintenance teams with project work
• Want flexibility with structure

Tools

Physical Boards

Advantages: High visibility, tactile, easy to modify Best Practices: Whiteboard, sticky notes, high-traffic area

Digital Tools

Trello: Simple, visual, good for small teams Jira: Comprehensive, advanced reporting, enterprise-grade Azure DevOps: Microsoft integration, built-in CI/CD LeanKit: Purpose-built for Kanban, advanced analytics Kanbanize: Advanced features, portfolio management Monday.com: Flexible, visual, non-technical teams

Using the Reference Files

When to Read Each Reference

/references/board-design-guide.md — Read when setting up new Kanban boards, optimizing workflow stages, or designing swim lanes and card layouts.

/references/wip-limits-optimization.md — Read when establishing or adjusting WIP limits, analyzing flow constraints, or resolving bottlenecks.

/references/metrics-and-analytics.md — Read when implementing Kanban metrics, creating CFDs, analyzing lead time distributions, or forecasting with throughput.

/references/advanced-practices.md — Read when implementing classes of service, scaling Kanban across teams, or integrating with other methodologies.