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Agile Estimation and Planning Workshop for Scrum Teams and User Stories
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Agile Estimation and Planning
A Quick Guide to Estimating Features and Stories in Agile Development
Peter Saddington, CSM CSPExecutive EditorAgileScout.com@agilescout
White Barrel LLC. © 2011 Peter Saddington
Peter Saddington, CSP CSMIndependent Enterprise Agile CoachRally Software Agile CoachExecutive Editor AgileScout.comAuthor – Scrum Pocket [email protected]+1.404.669.6662www.agilescout.comwww.scrumpocketguide.comTwitter: @agilescout
White Barrel LLC. © 2010 Peter Saddington
Product Backlog• A prioritized list of
features for the given product
• Stories are implemented based on their priority
• The TOP priority Features are put into iterations first
• Changes to the iterations are OK
White Barrel LLC. © 2010 Peter Saddington
Prioritization Factors to Consider• Financial value of
features• Costs of
implementation• Amount of risk
removed / added• Training on new
features• PO should be
enabled
White Barrel LLC. © 2010 Peter Saddington
Prioritization Sliders
White Barrel LLC. © 2010 Peter Saddington
Sizing Features for Release
White Barrel LLC. © 2010 Peter Saddington
Sizing Features for Release
White Barrel LLC. © 2010 Peter Saddington
• Sizing and estimation happens during an Iteration Planning Meeting
• “Commitment-driven iteration planning” is setting a goal for the iteration – What we will commit to and complete!
Atlanta Snow Day
White Barrel LLC. © 2010 Peter Saddington
• Snow day Atlanta on 1/10/2011
• You have volunteered to help move a mountain of snow off a parking lot
• How do we estimate how long this will take?
One Way to Estimate
White Barrel LLC. © 2010 Peter Saddington
1. Estimate the amount of snow
2. Measure how much snow you can move
3. Estimate the total duration
Size to Velocity
Size = f(Complexity + Amount)
White Barrel LLC. © 2010 Peter Saddington
OR
Velocity = f(# of team members, skills, learning, distractions, sickness, absence, changes, Murphy, ?)
Velocity
• Is the rate at which a team can produce working software
• Used for estimation and planning• Measured in non-time-referent terms
(Story points)• Should not be used as a measure of
comparison across teams
White Barrel LLC. © 2010 Peter Saddington
Size Estimate – Derive Duration
White Barrel LLC. © 2010 Peter Saddington
Estimation Guidelines• In Agile, we estimate
size, not duration• Estimates are
intentionally vague (in the beginning)
• Common estimate values include:– T-shirt sizes– Scale (1-10)– Fibonacci sequence
White Barrel LLC. © 2010 Peter Saddington
More Estimation Guidelines
• Size (complexity) is estimated– A story is estimated to be 5 story points in relative
complexity
• Velocity is measured– The Team can deliver 15 story points in a 2 week
sprint
• Duration is derived– Based on the Team’s measured velocity of 15 story points per
sprint, it will take the Team 4 sprints to deliver 60 story pointsWhite Barrel LLC. © 2010 Peter Saddington
Approaching Estimation• Assign points for smallest and medium sized stories• Size other stories by comparison or same size
White Barrel LLC. © 2010 Peter Saddington
Approaches to Sizing• Estimates are made by a GROUP not an
INDIVIDUAL– Points sizes never decay– Sizes don’t change based on estimator– Use consistent relative scale
• Use techniques– Analogy– Decomposition– Planning Poker
White Barrel LLC. © 2010 Peter Saddington
Estimate by Comparison / Analogy
3 points
5 points
8 points
13 points
White Barrel LLC. © 2010 Peter Saddington
Decomposition of a Story• Goal: Break big stories into smaller stories• Goal: Define stories that can fit into single iterations• Remember: A little effort helps a lot• Remember: A lot of effort only helps a little more
White Barrel LLC. © 2010 Peter Saddington
Techniques – Planning Poker1. Each team has a deck of cards – Each card has a point size2. Product Owner reviews a story (1 minute per story)
A. PO should have enough knowledge about the story to discuss details
3. Analysis (3 minutes per story)A. The story is briefly discussed with questions B. The discussion should be sufficient enough to determine the complexity and relative size of
workC. Compare story to other previously sized storiesD. Each team member selects a card that is his or her estimate
4. All cards are presented to the group at the same time5. Differences and outliers are discussed (1 minute)6. Re-estimate until estimates converge
A. Time-box card considerations if time is needed to discussB. Negotiate a happy mediumC. If one individual is in disagreement, ask them if the consensus is agreeable
White Barrel LLC. © 2010 Peter Saddington
Breaking Stories into Tasks with Planning Poker
Using Mike Cohn’s “Ideal Time vs Elapsed Time”:How long does a football game last?
Questions to ask yourself:1.How long would [task] take: 2.If it’s all you worked on…3.You had no interruptions…4.Had everything you needed to complete it?
White Barrel LLC. © 2010 Peter Saddington
Ideal vs Elapsed Time in Planning Poker
It’s much easier to estimate in ideal timeIt’s too hard to estimate in elapsed time
•Start with ideal time•Define what 1 story point equals (1 story point = 1 ideal day)•Estimate how many hours each person has available•Then gradually move team’s thinknig to unit-less story points (“This story is like that story”).•“Stop talking about how long it will take” – Mike Cohn
White Barrel LLC. © 2010 Peter Saddington
Summary• Remember the purpose of the iteration planning
meeting is to arrive at a commitment to an iteration goal or set of product backlog items.
• Story point estimation and task estimation takes time!• The purpose of the meeting is to come up with a list of
tasks and hours.• The tasks and estimates are a tool for determining
what we can commit to!• Inspect and adapt your velocity over time with 90%
confidence intervals
White Barrel LLC. © 2010 Peter Saddington
Resources Used in Presentation
White Barrel LLC © 2010 Peter Saddington
1. Mike Cohn’s Presentations on “Agile Estimating and Planning” – http://www.mountaingoatsoftware.com/presentations-estimating
2. Dean Leffingwell’s book – “Scaling Software Agility”
3. Jeff Patton – http://www.agileproductdesign.com
Questions?
White Barrel LLC © 2010 Peter Saddington