Estimation is a Waste of Time | The Power of Flow Metrics with Colleen Johnson
- Maria Chec
- Apr 24
- 4 min read
Breaking Free from the Estimation Trap: How Flow Metrics Drive Better Decisions
This article is a guest contribution from Maria Chec. Maria Chec is an award-winning Agile expert with 10+ years of experience in tech.Recognized as Agilist of the Year at Miro Canvas'24, she is a certified ProKanban trainer, international speaker and creator of Agile State of Mind on YouTube and Substack (mariachec.substack.com). Currently Maria works as a Product Operations Manager at OutSystems.
Tech teams often find themselves trapped in an endless estimation cycle, trying to forecast delivery dates with the precision of assembling a German car! “Shall we re-estimate the spillover? Or shall we close part of the story and open a new one for the new Sprint?” Those are the questions on the Product Owners minds during the Sprint Planning.
They are on a neverending quest to find the perfect estimate as if it were the Holy Grail.
“One day we’ll find the perfect estimate and live happily ever after.”
Yet, as Colleen Johnson, CEO of ProKanban.org, points out, this obsession with estimating is often a waste of time. Instead, she advocates for a shift towards flow metrics—simple yet powerful indicators that help teams understand and improve how work moves through their system.
00:00 Introduction to Kanban and Flow Metrics
03:39 Understanding Flow Metrics in Everyday Life
06:02 The Importance of Work Item Age
08:04 Challenges in Estimation and Forecasting
10:15 Real-Life Examples of Work Item Age
13:02 Risk Management in Project Timelines
15:49 Changing Conversations Around Estimates
18:38 Flow Metrics Stages of Grief
21:32 Improving Communication with Stakeholders
24:39 Conclusion
Why Flow Metrics Matter
Flow metrics offer a pragmatic approach to tracking value delivery. Rather than endlessly debating over the estimates, teams can rely on four key metrics:
Throughput – How many items are completed over a period.
Cycle Time – How long it takes for a work item to move from start to finish.
Work Item Age – How long an item has been in progress.
Work In Progress (WIP) – The number of active work items.
These metrics already exist in any system—they don’t require complex calculations or additional tracking efforts. By making them visible, teams can shift from speculation to informed decision-making.
The Work Item Age Blind Spot
One of the most overlooked yet crucial flow metrics is work item age—how long something has been in progress. Many teams neglect it, assuming that if work gets delayed, it’s an anomaly.
But as Colleen points out, delays are not exceptions; they are part of the system. If a feature takes 30 days to develop but sits for another 200 days due to dependencies, that’s the reality of how work flows. Understanding work item age helps teams prioritize what to complete first and avoid accumulating stale work.
A simple real-world analogy is food expiration dates. When milk nears its expiration, you decide whether to drink it or not. Similarly, when work sits in progress too long, it should trigger a discussion: Why is this still here? What’s stopping it from getting done?
The Estimation Trap and the Illusion of Precision
Traditional estimation methods often focus on breaking work into smaller tasks, assigning points or hours, and refining these numbers. Yet, despite all this effort, work still takes longer than expected. That’s because estimations usually account only for development time, ignoring factors like meetings, interruptions, dependencies, and external approvals.
Instead of striving for a perfect estimate, teams should embrace probability-based forecasting using historical data. If past cycle times indicate that most tasks are completed within 15 days or less, this data is far more reliable than an estimate pulled from thin air. It also allows teams to provide stakeholders with a realistic likelihood of completion, rather than a rigid deadline doomed to slip.
How Flow Metrics Shift Conversations
When teams start using flow metrics, it changes how they communicate about delivery. Instead of executives demanding a fixed date and teams scrambling to commit, conversations become about risk and probability.
For example, instead of saying, “The bathroom renovation will be done by March 31st,” you’d say
“Based on past data, there’s an 85% chance it will be done by March 31st. However, if issues arise, that likelihood may drop.”
This framing highlights the % of risk and allows for proactive decision-making. You can talk about adjusting scope or prioritizing critical tasks, rather than waiting for a crisis when the deadline inevitably slips.
Overcoming the Stages of Flow Metrics Resistance
When organizations first confront their real delivery times, they often go through five stages of grief.
Flow Metrics Stages of Grief by Colleen
1. Denial – “This data must be wrong.”
2. Resistance – “The work is wrong.”
3. Refinement – “We need to clean this up.”
4. Acceptance – “Oh. This is actually useful.”
5. Action – “Let’s use this to improve.”
Many teams try to “sanitize” their data, ignoring delays caused by external factors. Colleen emphasizes that all delays matter because they impact how long customers wait for value. Recognizing and addressing these realities is the first step toward meaningful change.
The Path to Predictable Delivery
Flow metrics provide a clear, actionable way to manage work without falling into the estimation rabbit hole. By tracking and acting on data that already exists, teams can improve delivery times, reduce uncertainty, and build trust with stakeholders.
Instead of promising unrealistic deadlines, they can communicate risk and negotiate trade-offs, leading to better planning and fewer last-minute surprises.
The real magic of flow metrics isn’t just in understanding work better—it’s in changing behaviors to make workflow faster. And that’s a conversation every Agile team needs to start having.
Looking to dive deeper into flow metrics? Check out the latest tools and resources at ProKanban.org and start making data-driven decisions today. You can also grab a copy of The Kanban Pocket Guide for more tips from Colleen Johnson and Prateek Singh.
Want to know more about Kanban and Flow Metrics? Contact Maria to run Applying Professional Kanban Training in your company:
As a Professional Kanban Trainer, Maria invites you to join the Applying Professional Kanban course. After passing the exam, you’ll get the Professional Kanban I (PK I) certification.
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