Scrum Bootcamp: Learn the Basics of Scrum Programming (2016)

Chapter 6. Estimation

The Scrum team should make their estimations during the planning stage. The purpose of these estimations is to analyze the user stories based on priority and the team’s capability. The product owner makes sure that the top-priority user stories are understandable, can be used for estimations, and are included in the project backlog.

Since the whole team is responsible for completing and delivering the project increment, extreme care should be taken when choosing user stories. The members of the team need to base their decisions on the increment’s target size and the overall effort needed in the project.

Important Note: The increment’s size is measured through story points. After determining the increment size, the team should estimate the effort needed using the data from previous sprints.

The Techniques Used in Estimation

When making estimates, focus on each user story’s degree of complexity/difficulty. Here are the scales that you can use in assessing the difficulty or complexity of user stories:

· The Numeric Sizing– This is a scale that ranges from 1 to 10.

· Shirt Sizes– (S, XS, M, L, XL, etc.)

· The Fibonacci Sequence– In this scale, you will add a number to the one that precedes it. The sum will be used as the next number.

The Poker Estimation Approach

In this approach, you will derive estimates by playing a poker-like card game. The whole team can help in implementing this approach. With Poker Estimation, you can generate reliable estimates without spending too much time or effort.

This approach requires multiple decks of playing cards. Using the numbers printed on the cards, follow the Fibonacci sequence. The cards’ numbers represent story points (i.e. the value used in measuring user stories).

Each member should have a deck of cards. You have to assign a moderator– this person will read the descriptions/explanations for the User Story. The product owner will answer any question brought up during the session.

The team members (also called“estimators”) should express their estimate by selecting a card privately. The estimators should keep their card hidden until all of them have chosen a card. Once everyone has selected a card, they should reveal their estimates simultaneously.

It’s possible that the estimations will vary significantly during the initial round. Each estimator should explain their estimates. Make sure that no personal questions are asked– the team members should focus on explaining their opinions/decisions.

While the users explain their opinions, the moderator should take notes. These notes can help the team in developing the user stories. Once a round is completed, each member should make another estimate. They will hide their card/s until all of them have made a selection. Then, they will reveal their cards at the same time.

Repeat this procedure until you get a single estimation. Keep in mind that the rounds required for estimation may vary, depending on the user stories you are working on.

The Methods Used in the Poker Estimation Approach

· Analogy– This method requires you to compare user stories. Basically, you should compare the current user story with the ones you have implemented. Since this method is based on actual data, it generates accurate results.

· Disaggregation– In this estimation method, you’ll split a user story into smaller ones. The user stories used in sprints normally last for three to six days; thus, if you encounter a User Story that lasts for seven days or more, you have to divide it into smaller, more manageable portions. As a bonus, this method helps you to make sure that you have comparable user methods.

· Expert Opinion– This method requires the feedback/suggestions of an industry expert. Since each team member is closely involved in the Scrum project, they have sufficient knowledge and experience regarding the subject matter; thus, they can be considered as“experts.”

· Here, the experts will base their opinions/estimates on their experience and knowledge, not on their intuition.

Conclusion

The poker approach is a fun and productive method that you can use to generate Scrum estimates. Since it allows people to share and discuss their opinions, the team will gain more information regarding the current user story.