Story Point-Agile Project Management

Story Points are the unit of measure to express an estimate to the overall effort that will require to implement a User Story.

When we estimate the story points, we assign a point value to each item. As the story points refer to the effort of the developer story, the teams estimate should include everything that would affect the effort.

When estimating the story points be sure to consider each of these factors.:

· Amount of work to do.
· Risk and uncertainty of the work.
· Complexity of the work.

Amount of work to do:

If there is more to do something, the estimated effort should be larger. Let’s say you have 2 web pages A and B. Web page A has only 1 Label and a Textbox, where you can enter text. On web page B, you have 100 text boxes. Despite having more fields, the second page is no more complex, has no addition risks. The only difference of these 2 pages is that you have more to do on the second page.

This means you need to give more story points to the second page. If we give 1 point to the page A. It does not mean you have to give 100 points to the page B. It would not require 100 times the effort. As story points are based on effort, we need to give 3 or 10 points.

Risk and Uncertainty:

If a team is asked to estimate a product item and the stake holder asking for it is unclear of what will be needed. Then that uncertainty should be reflected in the estimate. If implementing a feature involves some old code, then that risk should be reflected in the estimate.

Complexity:

In the above example web page B has 100 text fields, but these fields are not complex, as it is used just to enter texts. But if the fields consist of date picker/ calendar, date/SSN masking, fields that are in relation to each other where a user can enter his Credit Card details and the system validates and asks to enter his OTP/Pin. In this case, these fields are harder to implement as they are more complex. It will take more time and more chance that a developer can make mistake. This additional complexity should include in the estimate.

Effort is the unifying factory of the story point. Estimators consider how much effort is required to do the amount of work required by a backlog item. That effort is the function of volume of work. It is also the function of complexity, risk and uncertainty of a backlog item.

Story Points = fn[Volume of work, Complexity, Risk & Uncertainty]

When estimating story points, the team needs to include all work to fully implement an idea.
Story points are perfect for high level estimations and provides more value to the estimators.

Reference: Mike Cohn, Mountain Goat Software