The Danger of Anchoring in Agile Estimation
Anchoring is a cognitive bias where the first piece of information you hear disproportionately influences your judgment. In planning poker, it's the enemy of honest estimation - and it's everywhere.
How anchoring shows up in sessions
- The tech lead says "this feels like a 5" before voting starts
- A developer on the call explains how they'd approach it, implying a scope
- The Product Owner says "this should be quick" while reading the story
- The first card revealed in a sequential reveal pulls everyone else toward it
All of these are anchors. They shift estimates toward the anchor rather than toward what each individual actually thinks.
Why simultaneous reveal matters
The main defense against anchoring is simultaneous card reveal: nobody sees anyone else's vote until everyone has committed. This is the core reason tools like Play Scrum Poker Online exist - the structure enforces independence.
When teams reveal cards one at a time, or read estimates aloud sequentially, they're guaranteeing that later voters will anchor to earlier ones. The spread compresses artificially, and the information value of the vote is lost.
Other anchoring sources to eliminate
The PO's tone. Excitement or disappointment when discussing a story is an implicit anchor. Brief the PO to read stories neutrally.
Previous estimates. When re-estimating a story from a prior sprint, don't show the old estimate before voting. Let the team form fresh views.
Public "thinking out loud." When a senior developer explains their reasoning before the vote, less experienced team members anchor to it. Encourage thinking to happen privately before reveal.
When some anchoring is fine
Discussion after the reveal - when high and low voters explain their reasoning - is structured anchoring. It's intentional and useful. The information is shared after everyone has formed an independent view, not before.
Protecting estimation independence isn't about distrust. It's about getting the most information out of the collective knowledge your team already has.