Common Mistakes Teams Make in Scrum Poker and How to Avoid Them

Planning poker is one of the most effective agile estimation techniques available, but it is not foolproof. Teams that treat it as a box-ticking exercise rather than a genuine collaborative tool often find their estimates drifting from reality, their sessions running too long, or their team members disengaging. Awareness of the most common mistakes is the first step toward running estimation sessions that actually work.

Mistake 1: Insufficient Training and Onboarding

Many teams introduce planning poker without adequately explaining the underlying principles. New team members may not understand why the Fibonacci sequence is used, what story points actually represent, or how to think about complexity versus effort. This leads to estimates that are inconsistent from person to person, which undermines the entire purpose of the exercise.

How to avoid it: Before running your first planning poker session with new team members, invest time in explaining the fundamentals. Run a practice session with well-understood stories from previous sprints so that new members can calibrate their estimates against the team’s established norms. Revisit the basics periodically — especially after the team composition changes.

Mistake 2: Poorly Defined Work Items

Estimating a vague user story is guesswork, not estimation. When the acceptance criteria are unclear, when the story spans multiple systems or teams, or when the “definition of done” is ambiguous, team members have no shared basis for comparison. Estimates under these conditions will vary wildly — and even if a number is agreed upon, it is unlikely to reflect reality.

How to avoid it: Implement a definition of ready for user stories before they enter an estimation session. Stories should have clear acceptance criteria, known dependencies, and enough context for the team to discuss them meaningfully. The Product Owner should be available during planning poker to clarify questions in real time.

Mistake 3: Allowing Personal Bias to Influence Others

Planning poker is specifically designed to prevent anchoring — the tendency for people to be swayed by the first number they hear. The simultaneous card reveal is the mechanism that enforces this. But teams often undermine it by allowing senior developers, tech leads, or vocal team members to share their estimate before the cards are revealed.

How to avoid it: Enforce the simultaneous reveal as a non-negotiable rule. Remind the team that the goal of the private selection phase is to form an independent opinion. Facilitators should actively prevent discussion of specific numbers before the reveal. If one person’s estimate consistently dominates the discussion, explore whether that person is over-explaining their position or whether others are deferring unnecessarily.

Mistake 4: Rushing Through Discussion

When estimates diverge significantly, the instinct is often to split the difference and move on. This feels efficient but wastes the most valuable part of planning poker: the conversation that a disagreement triggers. The outlier who estimated a 13 when everyone else said 3 may have spotted a dependency that nobody else considered.

How to avoid it: Treat divergent estimates as a signal, not a problem. Give the highest and lowest estimators a chance to explain their reasoning without pressure. Use a time-box — three to five minutes per story — to keep discussions productive without cutting them short. The goal is not agreement for its own sake, but shared understanding.

Mistake 5: Treating Estimates as Fixed Commitments

Perhaps the most damaging mistake is treating a story point estimate as a promise. When estimates are used to hold team members accountable for delivery timelines, the estimation process becomes defensive. Developers start inflating their estimates to create buffer, which defeats the purpose of the exercise and erodes trust with stakeholders.

How to avoid it: Reinforce the principle that estimates are forecasts, not commitments. Story points measure relative complexity at a point in time, based on what the team currently knows. As requirements evolve and unknowns are resolved, estimates should be updated to reflect new information. Build a culture where re-estimation is normal, not an admission of failure.

Conclusion

Planning poker is a powerful tool when used thoughtfully, but its effectiveness depends entirely on how the team engages with it. By investing in proper training, ensuring stories are well-defined, protecting the integrity of the simultaneous reveal, taking divergent estimates seriously, and treating estimates as living approximations rather than fixed contracts, your team can transform planning poker from a routine formality into a genuine driver of shared understanding and better planning.