Concepts
Scrumpy is built on a concise and coherent model of the Scrum process comprised of the following concepts.
Portfolios
- A Portfolio is a collection of related Products and the Teams that work on them.
- Portfolios are completely independent of each other. They are useful if one is maintaining Backlogs for a number of Products and Teams across independent business areas.
Products
- A Product has a Backlog - a prioritised (i.e. ordered) list of User Stories with the most important Story at the top.
- A Product has a Reporting Period (weekly or monthly) which is used for charting and to calculate the Product Velocity.
- The Product Velocity for a Reporting Period is the total of the Story Points of all the Stories completed in that Reporting Period.
- As more Reporting Periods are completed a Product will have a Minimum, an Average and a Maximum Velocity.
- Determination of the Product Velocity is independent of the number of Teams working on a Product, Team composition, the length of a Team's Sprints and how contiguous the Sprints are.
- The Product Velocity can be used to forecast a completion date for the outstanding Stories on the Product Backlog and to give an indication of how likely it is that a Story will be completed by a specified date.
Releases
- A Release is a group of User Stories that will be deployed together.
- A Story can only be assigned to one Release (at any one time).
- The date on which the Release is likely to be complete is effectively the Forecast Date of its lowest priority Story.
Teams
- Teams work the Stories from a Product's Backlog in Sprints.
- A Team will have a Minimum, Average and Maximum Velocity. These are derived from the Sprint Velocities of all the completed Sprints.
- Knowing its Velocity enables a Team to determine how many Stories they can pull from the Product Backlog in the next Sprint and be likely to get them all done.
- Tracking the Team's Velocity helps to measure the effectiveness of improved working practices and to identify productivity problems.
- It is likely that a number of Teams will work on Stories from the same Product.
- It is possible that a Team may work on Stories from a number of different Products.
- It is likely that a Team's composition will vary from one Sprint to the next.
Sprints
- A Sprint is a pre-determined length of time (a time-box) in which a Team will work a number of Stories.
- The Sprint Velocity is the total of all the Story Points of the Stories completed during the Sprint by the Team.
- It is likely that Sprints may not follow one immediately after the other.
- It is possible (although not desirable) that Sprints may differ in length.
User Stories
- In isolation a Story does not have a priority (e.g. high, low, must, should, could etc). Stories have a priority relative to other Stories.
- Stories have a relative size expressed as the T-Shirt sizes which correspond to the following Story Points. This approach helps the Team consider the relative size of a number of the Stories. The Team typically talk in terms of the T-Shirt sizes when estimating. The application uses the equivalent Story Point number series for its Velocity calculations. By default the application uses the following geometric Story Point Series:
Story Size | Story Points |
---|---|
? | Unknown |
XS | 1 |
S | 2 |
M | 4 |
L | 8 |
XL | 16 |
XXXXL | 128 |
- If you prefer Scrumpy can be configured to use an alternative Story Point Size scheme e.g. Fibonnaci.
- Selecting a Story Size of "?" means that at this time we simple don't know how big the Story is. The Story becomes a prioritisable placeholder which won't effect any of the Product Velocity or Story Forecast Done Date calculations.
- Stories may be assigned to a Release.
- Stories may be assigned to a Team's Sprint.
- A Story has a date on which it was added to the Backlog. This is used to determine the rate at which work is being discovered.
- A Story has a date on which it was done. This is used to determine the rate a which work is being done i.e. the Product Velocity.
- A Story with no Done Date is not done.
- Stories have three Forecast Completion Dates derived from the Minimum, Average and Maximum Product Velocity. These are used to provide confidence levels for the outstanding Stories being Done by a specific date.