Estimation Framework
Overview
This framework uses a relative estimation approach, comparing tasks to past efforts and using the Fibonacci sequence (1, 2, 3, 5, 8, 13) to assign story points based on complexity and uncertainty. Consider time estimates, complexity levels, and unknowns to arrive at your final Fibonacci estimate.
Common Estimation Methods
Teams use different approaches to estimate work. Here are the most common methods:
T-Shirt Sizing
XS, S, M, L, XL - Simple and intuitive for high-level planning
Fibonacci Sequence
1, 2, 3, 5, 8, 13 - Used in this tool, reflects uncertainty
Powers of 2
1, 2, 4, 8, 16 - Common in technical teams
The concepts of the framework
Relative Estimation
Focus on comparing stories or tasks relative to each other rather than assigning fixed time estimates. Common methods include t-shirt sizing (XS, S, M, L, XL) and Fibonacci sequences.
Fibonacci Sequence
- Minor tweak
- Simple fix
- Standard adjustment
- Medium complexity
- Requires effort
- Intensive work
- Not enough context to estimate
- Needs more scoping, refinement, or planning
Stacey Matrix
The Stacey Matrix helps evaluate complexity and certainty of work. It plots Certainty (x-axis) vs Agreement (y-axis).
Understanding the Zones
Step-by-Step Estimation Process
Follow these steps to estimate
Step 1: Relative Time
| Size | Description |
|---|---|
| XS | Very quick task |
| S | Small task |
| M | Medium task |
| L | Large task |
| XL | Very large task |
| ? | Not enough context to estimate |
| Too large - needs breakdown |
Step 2: Complexity (Stacey Matrix)
| Complexity | Characteristics |
|---|---|
| Simple | Clear requirements, no ambiguity |
| Complicated | Requires expert knowledge |
| Complex | Needs experimentation or discovery |
| Chaotic | Emergency work or unknown process |
| ? | Not enough context to estimate |
| Needs more investigation |
Step 3: Unknowns Matrix
| Unknowns Level | Characteristics |
|---|---|
| Known-Knowns | Everything is understood |
| Known-Unknowns | Some research needed |
| Unknown-Knowns | Unfamiliar technology |
| Unknown-Unknowns | Highly ambiguous |
| ? | Not enough context to estimate |
| Too many unknowns |
Step 4: Final Estimate - Fibonacci
| Estimate | Guiding Factors |
|---|---|
| 1 - Minor tweak | XS-S, Simple, Known-Knowns |
| 2 - Simple fix | S-M, Simple or Complicated |
| 3 - Standard adjustment | M, Complicated, Known-Unknowns |
| 5 - Moderate challenge | M-L, Complex |
| 8 - High effort | L, Complex/Chaotic, Unknown-Unknowns |
| 13 - Major undertaking | XL, Complex/Chaotic |
| ? - Not enough context | ? selected in any previous step |
| Coffee selected in any previous step |
How this is used in sprint reporting
- Predictability - Consistent evaluation and better forecasting
- Velocity - Track story points completed per sprint
- Planning - Use historical velocity to plan future sprints
Interactive Estimator
Select your answers to calculate a story point estimate