Estimation
Estimation
- Helps make decisions
- Priority/sequencing of work
- Splitting/merging user stories
- How much can we do?
- Helps to build trust
Warning:
- Not only law of diminishing returns
- More might actually be less
Quick exercise
- What do you think is the relationship between time spent estimating and accuracy?
Group Exercise – Estimation
In your groups…
- How have you estimated work in the past?
- What is the relationship between work load and deadlines?
- Scope, Resources, Deadline, Quality…
- Which of these do you explicitly decide upon
- Which do you leave hanging?
- Who chooses each of these? Customers, users, developers, ???
Class Exercise – Estimation Observations
Report back from your group meeting
Individual Exercise – Estimation
Note, this example comes from Cohn’s “User Stories Applied”
Individually…
- From 1 to 10, estimate each based on average height at their shoulders:
- Labrador Retriever
- Vizsla
- Terrier
- Great Dane
- Standard Poodle
- French Bulldog
- Dachshund
- German Short-haired Pointer
Group Exercise – Estimation
In our groups of 4…
- From 1 to 10, estimate each based on average height at their shoulders:
- Labrador Retriever
- Vizsla
- Terrier
- Great Dane
- Standard Poodle
- French Bulldog
- Dachshund
- German Short-haired Pointer
- Be prepared to discuss the difference in the two experiences
Class Exercise – Compare Individual/Group
Discuss your differences between the individual exercise and the group exercise
Story Points
Story points
- Are relative
- Are arbitrary units of measure
- Each team defines how they see fit
- Combine complexity, size, risk, etc.
Who?
- The whole team
- Users/customers provide input, answer questions
- Developers make the call
NOTE!
- Estimates are the exclusive purview of developers
- No manager/product owner bullying.
Approaches (Must Haves Only)
Planning Poker
- Someone reads user story
- Product owner answers any questions
- Everybody selects an estimate from a collection of cards
- Everybody shows their estimate
- If “wide” variation, group discussion (with time box)
- Repeat until “near” convergence
- To organize this,
- Have decks of prepared cards (playing cards, 3x5 cards)
- One deck per person estimating (developers)
- Each deck has same set of numbers,
- 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
- 1, 2, 3, 7, 10, 17, 27
Group Exercise – Estimates
In your groups…
- Remember to make your meeting work
- Use planning poker on a few cards
- Notes
- Really, it is only developers who estimate
- Product owners, users, managers do not estimate
- Be prepared to discuss your answers
- Ah-ha’s
- Oh’s
Class Exercise – Estimates
What are the challenges at your organization to this style of estimation?
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