Definition of estimation:
An estimation is used to assign a measurable value to the work that must be done to complete a project or task. An estimate seeks to determine the effort or cost of a project or task.
It is important that when estimating stories, the team has a shared awareness of the "value" of the estimate. Regardless of whether a team uses the [Fibonacci sequence](/en/agile-dictionary/fibonacci sequence/ "Fibonacci Numbers in Scrum") sequence, t-shirt sizes, or other values.
Use of estimation:
The agile team must agree on a common estimate of the effort or duration required to complete a task after each team member's personal estimates. This can take the form of Planning Poker, for example. While estimating, it is important that the team gets a common understanding of the tasks at hand and that concerns of individuals are heard.
Advantages of estimation:
- Rough indication of the total duration, effort, or cost of a task.
- Reduced uncertainty about cost and duration.
- Guideline for estimating tasks and projects.
- Addressing potential challenges in a task.