The Scrum Core Team uses various tools and techniques such
as Task Estimation Meetings, Estimation Criteria, Planning Poker, Fist of Five,
etc. to estimate the effort required to accomplish each task in the Task List.
When estimating tasks, the core team create the Effort Estimated Task List
which is a list of tasks associated with the Committed User Stories included in
the ensuing Sprint. Now, let us analyze some of the important tools used by the
Scrum Core Team to estimate tasks. Here is an introductory video on estimating
tasks: http://www.scrumstudy.com/watch.asp?vid=614
The first tool or technique is the Task Estimation Meeting.
This meeting enables the Scrum Team to estimate the effort required to complete
a task or set of tasks and to estimate the people effort and other resources
required to carry out the tasks within a given Sprint. In Task Estimation
Meetings, the Scrum Team members use the Task List to estimate the duration and
effort for the User Stories to be completed in the Sprint.
One of the key benefits of this technique is that it enables
the team to have a shared perspective of the User Stories and requirements so
that they can reliably estimate the effort required. The information developed
in the Task Estimation Meetings is included in the Effort Estimated Task List
and it is used to determine the velocity for the Sprint. In this workshop, the
Scrum Team may use various techniques such as decomposition, expert judgment,
analogous estimation, and parametric estimation. Task Estimation Meetings are
sometimes also referred to as "Sprint Planning Meetings" - such
meetings may also be combined with Task Planning Meetings.
Next is
Estimation Criteria. The primary objective of using Estimation Criteria is to
maintain relative estimation sizes and minimize the need for re-estimation.
Estimation Criteria can be expressed in numerous ways, with two common examples
being story points and ideal time. For example, an ideal time normally
describes the number of hours a Scrum Team member works exclusively on
developing the project’s deliverables, without including any time spent on
other activities or work that is outside the project. Estimation Criteria make
it easier for the Scrum Team to estimate effort and enable them to evaluate and
address inefficiencies when necessary.
Planning Poker is another technique that can be used to
estimate tasks. Planning Poker, also called Estimation Poker, is an estimation
technique which uses consensus to estimate relative sizes of User Stories or
the effort required to create them. In Planning Poker, each team member is
assigned a deck of cards. Each card is numbered in a sequence and the numbers
represent complexity of the problem, in terms of time or effort, as estimated
by the team member. The Product Owner chooses a User Story from the Prioritized
Product Backlog and presents it to the team. The Scrum Team members assess the
User Story and try to understand it better before providing their estimate for
developing it. Then, each member picks a card from the deck that represents
their estimate for the User Story. If the majority or all team members select
the same card then the estimate indicated by that card will be the estimate for
that User Story. If there is no consensus, then the team members discuss
reasons for selecting different cards or estimates. After this discussion they
pick cards again. This sequence continues until all the assumptions are
understood, misunderstandings are resolved, and consensus or agreement is
reached. Planning Poker advocates greater interaction and enhanced
communication among the participants. It facilitates independent thinking by
participants, thus avoiding the phenomenon of group think.
Another technique that can be used in this regard is Fist of
Five. Fist of Five is a simple and fast mechanism to achieve consensus in a
group and drive discussion. After initial discussion on a given proposal or a pending
decision, the Scrum Team members are each asked to vote on a scale of 1 to 5
using their fingers. The value in using this technique is not only consensus
building but also driving discussion because each team member is asked to
explain the reason for their ranking. They are also given the opportunity to
express any issues or concerns. Once the team has discussed it, a collective
decision will be made. The number of fingers used to vote indicates the level
of agreement and desire for discussion:
1. One
finger: I disagree with the group's conclusion and have major concerns.
2. Two
fingers: I disagree with the group's conclusion and would like to discuss some
minor issues.
3. Three
fingers: I am not sure and would like to go with the group's consensus conclusion.
4. Four
fingers: I agree with the group's conclusion and would like to discuss some
minor issues.
Five fingers: I wholeheartedly agree with the
group's conclusion.
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