Story points

Story points are units of relative size used in estimating tasks in agile software development.

Usage

Typically when a list of tasks to be done is created (in agile development usually called a backlog and consisting of user stories) the team estimates the size of each task on the list in relation to other tasks. Different techniques are used to obtain the estimate - triangulation, planning poker, paired comparisons or voting. The result of the process is that at the end each task on the list gets a numerical value describing its relative size to other items on that list.

The values can be then used to estimate when the tasks can be completed knowing the team velocity (or how many story points they typically do per iteration). Since story points are relative representations of subjective estimates they can't be compared between teams and contexts, but can be used to estimate and plan development in an agile project.

References

[1] Mike Cohn, "Agile estimating and planning", Prentice Hall, 2005.

[2] E. Miranda, "Improving Subjective Estimates Using Paired Comparisons," IEEE Software, January 2001.