Agile Estimation Techniques

Estimation is about understanding, not precision. Good estimation creates shared understanding and enables planning. Poor estimation either overpromises or pads excessively. This guide covers practical estimation techniques for agile teams.

Estimation Approaches

Story Points

Relative Estimation

STORY POINTS
════════════

WHAT ARE STORY POINTS:
─────────────────────────────────────
Relative measure of:
├── Complexity
├── Effort
├── Uncertainty
├── Combined into single number
├── Not hours
└── Relative sizing

FIBONACCI SEQUENCE:
─────────────────────────────────────
1, 2, 3, 5, 8, 13, 21

Why Fibonacci:
├── Larger = less precision
├── Forces choice between options
├── Acknowledges uncertainty
├── Gap grows with size
└── Reflects reality

REFERENCE STORIES:
─────────────────────────────────────
Establish baseline:
├── 1 point: "Add field to form"
├── 3 points: "New API endpoint"
├── 5 points: "Feature with tests"
├── 8 points: "Complex integration"
├── 13 points: "Should split"
├── Team calibration
└── Compare new to reference

WHAT POINTS CAPTURE:
─────────────────────────────────────
├── Technical complexity
├── Amount of work
├── Risk/uncertainty
├── Knowledge gaps
├── Dependencies
├── Not just time
└── Holistic view

Planning Poker

Team Estimation

PLANNING POKER
══════════════

HOW IT WORKS:
─────────────────────────────────────
1. Read story aloud
2. Answer clarifying questions
3. Everyone selects card (hidden)
4. Reveal simultaneously
5. Discuss differences
6. Re-vote if needed
7. Consensus or average

EXAMPLE SESSION:
─────────────────────────────────────
Story: "User password reset"

Round 1 (reveal):
├── Alice: 3
├── Bob: 8
├── Carol: 5
├── Dave: 5
└── Wide spread - discuss!

Discussion:
├── Bob: "Need email service integration"
├── Alice: "We have email helper already"
├── Carol: "What about rate limiting?"
├── Team: "Good point, add to story"
└── New understanding

Round 2 (reveal):
├── Alice: 5
├── Bob: 5
├── Carol: 5
├── Dave: 5
└── Consensus: 5 points

WHY IT WORKS:
─────────────────────────────────────
├── Prevents anchoring (simultaneous)
├── Surfaces different perspectives
├── Discussion builds understanding
├── Team owns estimate
├── Wisdom of crowd
└── Collaborative

TIPS:
─────────────────────────────────────
├── Time-box discussions (2-3 min)
├── Defer to implementer
├── If wide spread, discuss more
├── Large items (>13): split
├── Uncertain: default higher
└── Efficient meetings

T-Shirt Sizing

Quick Estimation

T-SHIRT SIZING
══════════════

SIZE DEFINITIONS:
─────────────────────────────────────
XS: Trivial (< 1 day)
S:  Small (1-2 days)
M:  Medium (3-5 days)
L:  Large (1-2 weeks)
XL: Epic (break down first)

WHEN TO USE:
─────────────────────────────────────
├── Roadmap planning
├── Early backlog grooming
├── Quick estimates
├── High-level planning
├── Not sprint-ready
└── Rough sizing

PROCESS:
─────────────────────────────────────
1. List items to estimate
2. Start with obvious ones
3. "Is this S, M, or L?"
4. Quick team consensus
5. Move to next
6. Refine later

CONVERT TO POINTS:
─────────────────────────────────────
When sprint-ready:
├── XS → 1 point
├── S → 2-3 points
├── M → 5-8 points
├── L → 13+ (split first)
├── Rough conversion
└── Detail later

Affinity Mapping

Batch Estimation

AFFINITY ESTIMATION
═══════════════════

FOR MANY ITEMS:
─────────────────────────────────────
When you have many items to estimate:

1. Setup
   ├── Columns: 1, 2, 3, 5, 8, 13
   ├── Cards on table
   └── Team around table

2. Silent sorting
   ├── Pick up any card
   ├── Place in column
   ├── No talking
   ├── Can move others' placements
   └── 5-10 minutes

3. Discussion
   ├── Review placements
   ├── Discuss disagreements
   ├── Adjust as needed
   └── 10 minutes

4. Finalize
   ├── Record estimates
   ├── Note large items to split
   └── Done

EXAMPLE:
─────────────────────────────────────
│ 1 │ 2 │ 3 │ 5  │ 8  │ 13  │
├───┼───┼───┼────┼────┼─────┤
│ A │ D │ G │ J  │ M  │ P   │
│ B │ E │ H │ K  │ N  │     │
│ C │ F │ I │ L  │ O  │     │

30 items estimated in 20 minutes!

WHEN TO USE:
─────────────────────────────────────
├── New project kickoff
├── Many backlog items
├── Quarterly planning
├── Quick calibration
└── Efficient for volume

Improving Estimates

Learning from Experience

IMPROVING ESTIMATION
════════════════════

TRACK ACCURACY:
─────────────────────────────────────
Record for each story:
├── Estimated points
├── Actual effort
├── Surprises encountered
├── What was missed
└── Data for learning

RETROSPECTIVE REVIEW:
─────────────────────────────────────
Discuss:
├── Which estimates were way off?
├── What did we miss?
├── Any patterns?
├── How to estimate better?
└── Continuous improvement

COMMON ESTIMATION ERRORS:
─────────────────────────────────────
Underestimating:
├── Hidden complexity
├── Integration work
├── Testing effort
├── Review/feedback cycles
├── Dependencies
└── Add buffer

Overestimating:
├── Unfamiliar technology (less scary after)
├── Similar past work
├── Existing solutions
└── Adjust calibration

GUIDELINES:
─────────────────────────────────────
├── Break down large items
├── Include testing in estimate
├── Account for reviews
├── Don't estimate > 13 points
├── When uncertain, go higher
├── It's okay to be wrong
└── Learn and improve

GitScrum Estimation

Tool Support

GITSCRUM FOR ESTIMATION
═══════════════════════

EFFORT POINTS:
─────────────────────────────────────
├── Estimate on tasks
├── Sprint planning view
├── Capacity tracking
├── Velocity calculation
└── Built-in support

PLANNING SESSION:
─────────────────────────────────────
├── Backlog refinement view
├── Add estimates
├── Team discussion
├── Record decisions
└── Efficient sessions

VELOCITY TRACKING:
─────────────────────────────────────
├── Points completed per sprint
├── Average velocity
├── Trend over time
├── Planning data
└── Predictability

ESTIMATION HISTORY:
─────────────────────────────────────
├── See past estimates
├── Compare to actual
├── Reference stories
├── Learn from history
└── Improve over time

Best Practices

For Estimation

1. Relative, not absolute — Compare to reference
2. Team estimates — Not individual
3. Discussion > precision — Understanding matters
4. Split large items — Nothing > 13 points
5. Track and learn — Review accuracy

Anti-Patterns

ESTIMATION MISTAKES:
✗ Manager dictates estimates
✗ Precise hour estimates
✗ No reference stories
✗ Skip discussion
✗ Estimate solo
✗ Never review accuracy
✗ Punish wrong estimates
✗ Estimate huge items

Related Solutions

• Task estimation techniques
• Sprint planning best practices
• How to track sprint velocity for engineering teams