When Everyone Can See the Plan Fall Apart

Feb 27 / Jim Benson
Image of Daniel Kahnemann work by nrkbeta.no is licensed under a Creative Commons Attribution-Share Alike 3.0 Norway License.
Teams consistently miss their planning estimates not because they're bad at math, but because of a cognitive pattern Daniel Kahneman called the planning fallacy — the hardwired tendency to imagine the best-case path to completion and treat it as a prediction. In groups, this gets worse: social pressure in planning sessions turns estimates into performances of competence rather than honest forecasts, dependencies between people's work get invisibly optimized away, and without a shared record of actual throughput, every sprint gets planned from hope rather than evidence.

The structural fix isn't better estimation techniques — it's making reality visible before it becomes a crisis. A shared team kanban board lets everyone see overload forming, tracks the team's actual Done history as a planning baseline, and surfaces blocked work while there's still time to respond. Paired with a fifteen-minute review of the last cycle's Done column before every planning session, the board gives teams what Kahneman called the "outside view" — planning from what actually happened rather than what everyone hopes will happen this time.

When Everyone Can See the Plan Fall Apart

What Kahneman's Research on Cognitive Bias Means for Teams That Keep Missing Estimates

This is part of the Behavioral Economists series. Start with The Science of Finishing Things on Humane Work.

Your sprint planning session probably goes something like this: everyone gives their estimates, the numbers get added up, and the total lands right at the theoretical edge of what your team can do in two weeks. Not what you'll actually do. What you could do if nothing unexpected happened, nobody got sick, no priority shifted, no dependency got stuck.

Then Thursday of week two arrives.

Daniel Kahneman spent fifty years documenting the mechanism behind this. His term for it — the planning fallacy — describes our systematic tendency to construct optimistic scenarios and treat them as predictions. We imagine the smooth path to completion and anchor our estimate there. We don't imagine the realistic path. We never do.

In individuals, this is bad enough. In teams, it compounds.

The Three Ways Group Planning Makes It Worse

The planning fallacy operates in individuals. Teams add three amplifiers that make it almost impossible to correct without structural help.

Social pressure tightens estimates. When someone announces their task estimates in front of their manager and peers, they're not just forecasting — they're making a public commitment. Conservative estimates feel like admissions of slowness. The estimate becomes a performance of capability rather than a prediction of reality. So estimates tighten, optimism compounds, and the planning fallacy gets reinforced by the group dynamics meant to keep everyone aligned.

Dependencies get optimized away. Each person estimates their own work in isolation. Nobody estimates the handoff time, the waiting time, the clarification loop, the review queue. The gaps between work are where projects actually bleed time — and they're invisible in any individual estimate.

There's no shared record of actual throughput. Without a visible history of how long work actually takes, every planning cycle starts from intuition rather than evidence. Each sprint gets planned as if the last one didn't happen.

Kahneman calls this the inside view — building estimates from the imagined scenario rather than from base rates of how similar things have gone before. Teams are almost always planning from the inside view.

What a Shared Visual Board Changes

A team kanban board doesn't fix the planning fallacy. Nothing does — Kahneman is pretty clear that it's wired in. What the board does is create three mechanisms that let the team correct for it in real time, before a Thursday reckoning.

What the board does: make overload visible before it becomes a miss.

When every team member's work is on a shared board, you can see when someone has six things in progress before it costs you a deadline. You can see when a card has been sitting in Doing for three days longer than estimated. You can see the gap between the optimistic plan and the actual state of the work — while there's still time to respond.

The Done column is the team's actual track record. Most sprint planning sessions involve a lot of conversation about capacity and very little reference to evidence. But the evidence exists, right there: how much the team actually completed in each of the last six cycles. Reviewing it before planning — fifteen minutes, three questions — grounds the next plan in reality rather than optimism. What actually got done? What took longer than expected? What kept getting blocked?

This is what Kahneman would call an outside view: planning from base rates rather than best-case scenarios. The Done column provides it.

Blocked cards become legible to the whole team. When a dependency is stalling a card, the board makes it visible. Other people can see it. The team can respond — redistribute work, surface the problem, adjust scope — before the blockage cascades silently into a missed commitment.

Building the Outside View Into Your Team's Rhythm

The simplest structural change: before any planning session, spend fifteen minutes with the team's Done column from the last cycle. Ask together:

  1. How much did we actually complete versus what we planned?
  2. What took longer than expected, and why?
  3. What kept getting interrupted or blocked?

This is a retrospective in its most stripped-down form — not a ceremony, just an evidence review. The answers calibrate the next plan against what the team actually does rather than what it hopes to.

Pair this with individual WIP limits. When each person's in-progress work is visible and bounded — three items, not eight — the team can see overload forming before it affects delivery. A WIP limit doesn't just help individuals finish more. It gives the team a real-time view of where capacity is being stressed.

The Manager's Role: Making Honest Estimates Safe

Kahneman's research makes something uncomfortable explicit: the planning fallacy gets worse in environments where conservative estimates feel politically risky. If your team consistently underestimates, the first question isn't "how do we estimate better?" — it's "why does the team feel they can't be honest about what's realistic?"

A visible shared board shifts some of that dynamic. When throughput is on record for everyone to see, estimates become less about managing impressions and more about engaging with evidence. The conversation moves from "how long do you think this will take?" (which invites performance) to "here's how long this type of work has taken us" (which invites calibration).

Collaborative aid is part of the same shift — team members actively helping when blocked work becomes visible, rather than waiting for it to become a crisis. That's the environment where honest planning is possible. Where the social pressure in a planning session is toward realism, not optimism.

For the individual board mechanics behind these patterns, see The Optimistic Brain Is a Terrible Project Manager on the Personal Kanban blog. For the leadership perspective on slow thinking and judgment, see Slow Thinking Is a Leadership Skill at Modus Cooperandi.

Modus Institute helps teams and organizations work visually, limit overload, and build systems that actually improve over time. Explore our courses and live events.

For the practitioner's guide to Personal Kanban, start with the book. For weekly essays on work, flow, and being human while getting things done, join us at Humane Work.

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