Story points & Story points estimation

What are story points?

Story point is a relative weight given to each user story.
It is a measure of the amount of work involved.
Both complexity and the size of the work are factored while estimating the story points.
Story points of a user story indicates the relative weight of the story when compared to other stories in the project.
Generally people use the Fibonacci series (0,1,2,3,5,8,13,21…..) to allocate story points to stories.
The smallest story is given a number 1, the next bigger one 2 etc…
A story with story point 5 indicates that it is approximately 2 times bigger than a story with story point ‘2’, or five times bigger than a story with story point ‘1’.

Detailed story point estimation happens during the first half of the sprint planning meeting (iteration planning meeting)
During the sprint planning meeting (in some cases prior to the sprint planning meeting), the product owner explains the user story to be estimated to the team
Answers all the questions by the team regarding the user story / stories
Each team member gives a number to the story, based on the Fibonacci series.
This is an individual exercise.
While deciding on the user story for the story, the team member is not supposed to discuss with other team members, except for asking doubts about the feature to be developed as per the user story.
When the scrum master say ‘Show’, all team members displays their individual estimates (story points) for the story under consideration
Discussions starts
Finally, the team discusses, debates and converge into a single estimate for the story, and that becomes the agreed upon story point for the user story.
The process continues, till all the user stories planned for the sprint are estimated