Story Points And Estimation | Agile Planning

What are Story Points?

Story points are a unit of measure used in Agile project management to estimate the effort required to implement a user story. Unlike hours or days, story points are a relative measure that takes into account the complexity, the amount of work, and the risk involved in delivering a user story.

The idea is to allow teams to assess the effort required for different user stories without getting bogged down in precise time estimates. This helps in understanding how much work can be completed in a sprint.

Why Use Story Points?

The use of story points provides several advantages:

Focus on Complexity: Story points encourage teams to consider the complexity and uncertainty of tasks rather than just time.
Encourages Team Collaboration: Estimating story points is often done collaboratively, promoting discussion and shared understanding.
Better Predictability: Over time, teams can track their velocity (the number of story points completed in a sprint) to improve future estimations.

How to Estimate Story Points?

Estimating story points usually involves a few steps:

Identify a Reference Story: Select a simple user story that the team has previously completed and assign it a point value, often 1 or 2.
Compare Other Stories: Using the reference story, compare other user stories to it. If a new story is considered twice as complex, it might be assigned twice the points.
Use Planning Poker: A popular method for estimating story points where team members use cards to simultaneously assign points to a user story, facilitating discussion and consensus.

Example: If a reference story is estimated at 2 points and a new story is deemed more complex, the team might decide on 3 points for the new story.

Common Story Point Scales

There are several common scales used for story points. Here are a few examples:

Fibonacci Sequence: 1, 2, 3, 5, 8, 13, 21...
T-shirt Sizes: XS, S, M, L, XL...
Linear Scale: 1, 2, 3, 4, 5, 6, 7, 8...

Each team may choose a scale that best fits their workflow and understanding.

Calculating Velocity

Velocity is a measure of how many story points a team can complete in a sprint. It is calculated by summing the story points of all completed user stories at the end of a sprint.

Example: If a team completes 5 user stories with the following story points: 3, 5, 2, 8, 3, their total velocity for the sprint would be:

Total Velocity = 3 + 5 + 2 + 8 + 3 = 21 Story Points

Conclusion

Story points and estimation are fundamental aspects of Agile planning that aid teams in understanding their workload and enhancing collaboration. By employing relative measures of effort, teams can better predict their performance and make informed decisions about future sprints.