Story points are a common way to estimate the relative effort, complexity, and uncertainty of product backlog items, such as user stories or features. They help product managers and development teams plan, prioritize, and deliver value to customers. But how do you use story points effectively? Here are some tips to help you get started.
Story points are a unit of measurement that reflects the size of a product backlog item, not the time it takes to complete it. They are based on factors such as the amount of work, the level of difficulty, the risk of unknowns, and the dependencies involved. For example, a simple and well-defined task might be worth one story point, while a complex and ambiguous one might be worth eight or more.
Defining what a story point represents is crucial, as the methodology does not clearly define it. Each team should be able to do that, which may vary between teams. Story points should represent the effort required to implement a product backlog item relative to other items. For example, a 2-point task should take roughly twice as long to implement as a 1-point task.
There are different methods to assign story points to product backlog items, but one of the most popular ones is planning poker. Planning poker is a collaborative and interactive game that involves the whole team. Each team member gets a set of cards with numbers that represent story points, usually following a Fibonacci sequence (1, 2, 3, 5, 8, 13, etc.). The product manager or the product owner presents a product backlog item and explains its requirements and acceptance criteria. Then, each team member secretly picks a card that reflects their estimate of the item's size. After everyone has chosen a card, they reveal them simultaneously and compare their estimates. If there is a large discrepancy, the team discusses the reasons and assumptions behind their estimates, and tries to reach a consensus. If there is no consensus, the team repeats the process until they agree on a story point value for the item.
While this method sounds complex, it was always my favorite exercise. Working this way not only allows assigning the correct story points, it also gets the team involved in understanding deeply what we want to build, how this is solving the problem for our users, and we discuss alternatives. Personally, I use this time for more than just scoring a task; it's to make sure everyone is excited about what's next and how it moves us closer to our goals.
Story points can be a beneficial tool for product managers and development teams, as they help to communicate the value and priority of product backlog items to stakeholders and customers. Story points also allow teams to align expectations and understanding of scope and complexity, while improving the accuracy and reliability of estimates. Additionally, story points are flexible, allowing teams to adapt to changing requirements and conditions. Lastly, story points can be used to measure velocity and productivity, by tracking how many story points can be delivered in a given time frame.
Story points are relative and subjective, which means that different teams might have different interpretations and scales of what a story point means. To ensure consistency and clarity, it is important to calibrate story points across teams and projects. One way to do this is to use a reference story, which is a product backlog item that has a known and agreed-upon story point value, and that serves as a baseline for comparison. For example, if a team has a reference story that is worth three story points, they can use it to estimate other items by asking themselves: is this item bigger, smaller, or similar to the reference story? Another way to calibrate story points is to review and revise them regularly, especially after completing a sprint or an iteration, and after receiving feedback from customers and stakeholders. This helps the team to refine their estimates and align them with the actual effort and value delivered.
Story points are a useful tool for product managers and development teams, however, they can come with some challenges and risks. To avoid common pitfalls when using story points, remember that they are not a measure of time, output or precision. They should be realistic and reasonable based on the team's experience and knowledge, and should be updated as the team learns more about the product backlog item, its requirements, and its dependencies. Additionally, story points should not be used as a performance metric as they do not reflect the quality, impact or value of the work delivered.
Make sure to refine estimates over time. As the team gains more experience and completes more product backlog items, they can refine their estimates and improve their accuracy. It's important to regularly review and adjust estimates to ensure they remain relevant.
Estimating product backlog items should be a collaborative effort involving the entire development team. This helps to ensure that everyone has a shared understanding of the work involved and the level of effort required.