How do Scrum Teams Estimate Tasks in a Project?
Task planning and estimation is vital to develop products iteratively in accordance with the
requirements specified in the Prioritized Product Backlog. The Scrum Team, in Task Estimation
Meetings, estimates the effort required to accomplish each task in the Task List. The result of this
process is an Effort Estimated Task List.
The Scrum Team uses the Task list, a comprehensive list containing all the tasks to which the
team has committed for the current Sprint, to develop an Effort Estimated Task List. The Task List
must include any testing and integration efforts so the product increment from the Sprint can be
successfully integrated into the deliverables from previous Sprints. Even though tasks are often
activity based, the level of granularity to which the tasks are decomposed is decided by the Scrum
During Task Estimation Meetings, the Scrum Team uses the Task List 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. 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 may also be combined
with Task Planning Meetings.
To maintain relative estimation sizes and minimize the need for re-estimation the team uses
estimation criteria. 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.
The output of task estimation is the Effort Estimated Task List. It is a list of tasks associated with the
User Stories committed to in a Sprint. Typically, the accuracy of estimates varies with team skills.
Estimated effort is expressed in terms of the estimation criteria agreed on by the team. This Effort
Estimated Task List is used by the Scrum Team during Sprint Planning Meetings to create the Sprint
Backlog and Sprint Burndown Chart.