Estimate a User Story

You can't build a great building on a weak foundation. You must have a solid foundation if you're going to have a strong superstructure. - Gordon B. Hinckley

Estimating User Stories is an important FOUNDATION activity in Scrum projects. With experience and practice teams will get better at estimation, which will help to plan and forecast production Release Schedules and project completion dates.

Let's discuss few popular methods out of many available.

1. Planning Poker (Most Popular Method using Fibonacci series)

• Estimating effort required for a user story relative to each other.
• The TRUE democratic process, time boxed. Scrum Master may get involved to break the impasse.
• A Scrum team member will read user story out loud, which will initiate the discussion for clarification and better understanding.
• At end of discussion, each development team members will pick and raise a numbered card depending upon effort involved as per his/her understanding and analysis.
• Member with the highest and the lowest number will give their reasons for the estimation.
• Team members will discuss further and ask questions until all are in the agreement.

2. Estimating by 'Ideal Time'

• Estimating the size of User Story with work hours required to complete. Assuming those work hours are focused and without interruptions.
• These usually works for the projects where teams are seasoned and established. They have a fairly good idea about the work needs to be done and how long it usually takes. Repetitive activities with few variances.
• Team's Velocity per Sprint has been established. So, project forecasts and Release Planning are more accurate.

3. Using T-shirt size terminology

• Sizing User Stories with day-to-day T-shirt size terminology like S, M, L, XL etc.
• This method is used when teams are new to the concept of the Scrum and are involved in less technical projects. So, members can easily relate and adapt easily.
• It still serves the purpose of Agile methodologies and Scrum Framework which is to provide estimation for Sprint planning.

Why should we estimate a User Story?

• So, Scrum team will actually start thinking about the work involved. The subconscious mind will start working on it while the conscious mind is busy doing current work on hand. Multi-tasking without any loss of productivity!
• Your Scrum planning meeting will be quick and effective. You will have more time for asking questions to understand the requirements and deciding on "Acceptance Criteria", test cases etc.
• To calculate team's Velocity per sprint, so that we can forecast project completion, budget etc.
• It will help us to forecast, plan and prepare for production Release planning.

Who estimates a User Story?

• Development team - They will always have the final say because they do the actual work.
• Experienced Product Owner, who is aware of Team's capacity/capability can usually provide initial estimate while writing User stories and ordering Product Backlog items.

When should we estimate a User Story?

• It's a continuous process till the User Story is completed and accepted.
• At the time of creating/writing a User Story.
• During Product Backlog Grooming sessions.
• During Sprint planning session.

When should we calculate a User Story points?

• During Sprint planning session. This will help us to select Sprint Backlog item based on team's Velocity.
• Before Sprint Review meeting, so that we can compare our estimated value with completed actual value. Delays can be explained to the stakeholders.
• At end of Sprint Review meeting, to calculate accepted stories vs delivered stories. The difference will give us information about incomplete work.
• The reasons for deviation can be discussed during Sprint Retrospect meeting to discuss what was missed and how to improve?