Three-Point Estimation vs Planning Poker: Which Should You Use?
Both methods acknowledge that estimates are uncertain. They differ in how they handle that uncertainty and what they produce. Both are covered, alongside the rest of the technique family, in the agile estimation techniques guide.
How three-point estimation works
Each estimator provides three values for each story:
- Optimistic (O): best case, everything goes right
- Most likely (M): what you'd expect normally
- Pessimistic (P): worst case, things go wrong
These combine into a weighted average: (O + 4M + P) / 6
This gives you an expected value with an implicit confidence range. It's particularly popular in traditional project management (PERT analysis) and works well when you need a probability-weighted number for scheduling.
How planning poker differs
Planning poker produces a single relative estimate (story points) through consensus. It doesn't try to model the uncertainty mathematically; instead, the discussion between high and low voters surfaces the uncertainty explicitly, and the team resolves it before committing.
When three-point wins
- You need to produce schedule estimates with confidence intervals
- You're estimating large pieces of work (epics, features) rather than user stories
- Stakeholders want to understand risk quantitatively, not just see a single number
When planning poker wins
- You're estimating at the story level for sprint planning
- You want the discussion that surfaces hidden complexity
- Your team is already calibrated on a relative scale
- Speed matters: three-point is slower per story
Can you combine them?
Yes. Some teams use three-point estimation for roadmap-level planning (quarters, big features) and planning poker for sprint-level work. The two operate at different granularities and serve different audiences.
Neither method removes estimation error. They give you different ways to understand and communicate the uncertainty.
