Effort Estimation 1 - Non-algorithmic Techniques

Question 1

Cone of Uncertainty

Answer 1

Uncertainty decreases with more information about the project / activities

Question 2

Top-Down estimation

Answer 2

• Uses a high-level work breakdown structure
• Suited for a quick first-pass

Question 3

Bottom-up

Answer 3

• Uses a detailed work breakdown structure
• Estimate cost of each component separately
• Add these costs to produce a final cost estimate

Question 4

Delphi Technique - Procedure

Answer 4

1. The moderator distributes the product / project definition to the estimators
2. Each estimator completes the estimation anonymously
3. The moderator prepares and distributes a summary of the estimations together with unusual rationales provided by the estimators
4. The estimators complete a re-estimation (again anonymously) based on the results of the previous round
5. The process is iterated for as many rounds as required!

Question 5

Delphi Technique - Advantages

Answer 5

• Iterative, team based, collaborative estimating
• Less biased than individual estimation
• Does not require historical data
• Can be used for both high-level and detailed level estimation
• Simple and cheap!

Question 6

Delphi Technique - Disadvantages

Answer 6

• May be hard to find more than one expert
• Estimations are not reproducible and cannot be reviewed
• Possible to reach consensus on an incorrect estimate, people may not be skeptical enough
• Can develop false sense of confidence

Question 7

Planning Poker Cards - Procedure

Answer 7

1. At first the story is briefly discussed
2. Then each team member chooses from his own deck the numbered card that represents his estimate of how much work is involved in the story under discussion
3. All estimates are kept private until each participant has chosen a card
4. At that time, all estimates are revealed and discussion can begin again
   -> Highest and lowest estimation must be justified

Question 8

Story Point

Answer 8

• A unit used to estimate the difficulty of implementing a given user story
• Considered aspects: complexity and risks

Question 9

Team Velocity

Answer 9

• Average number of story points successfully implemented in sprints
• Each team has its own velocity
• If the velocity is known and constant, story points can be matched to sprints!

Question 10

Estimating a complete project

Answer 10

1. To map the story points to classic effort quantities the team productivity must be known
   - Velocity: average
2. If a team has a very stable velocity, the number of sprints estimated to implement all backlog entries is fairly accurate
3. Can also be used to clean up a backlog that has become too large
4. The product owner needs such an estimate for release planning