Estimating Work

Estimation Approaches

Story Points

Relative complexity, not time.

| Points | Complexity | |--------|------------| | 1 | Trivial, well understood | | 2 | Simple, minor unknowns | | 3 | Moderate complexity | | 5 | Complex, some unknowns | | 8 | Very complex, significant unknowns | | 13 | Extremely complex, many unknowns | | 21+ | Too big, needs decomposition |

T-Shirt Sizing

For high-level estimates.

| Size | Relative Effort | |------|-----------------| | XS | Hours | | S | 1-2 days | | M | 3-5 days | | L | 1-2 weeks | | XL | 2-4 weeks |

Estimation Factors

Consider:

• Complexity: How difficult is the problem?
• Uncertainty: How much is unknown?
• Effort: How much work is involved?
• Risk: What could go wrong?

Estimation Techniques

Planning Poker

1. Present the task
2. Everyone selects estimate privately
3. Reveal simultaneously
4. Discuss outliers
5. Re-estimate if needed

Three-Point Estimation

Expected = (Optimistic + 4×Likely + Pessimistic) / 6

Reference Stories

Keep calibration stories:

• "This 3-point story took 2 days"
• "This 8-point story took a week"

Common Pitfalls

• Anchoring: First estimate biases others
• Optimism: Underestimating unknowns
• Scope Creep: Original estimate doesn't match final scope
• Ignoring Overhead: Code review, testing, deployment

Tips

1. Estimate in ranges, not points
2. Include buffer for unknowns
3. Track actual vs. estimated
4. Re-estimate when scope changes
5. Don't estimate in hours (use relative sizing)