Story Points: how to estimate task complexity in Agile methodologies?

What are story points and where did this concept come from?

Story points are a clever agile project management tool that allows teams to assess how big and difficult a task is. Importantly, these are not hours, but difficulty points that indicate: size (how much needs to be done?), complexity (how technically difficult is the task?) and risk (how uncertain is it?). This is a comparative estimate. The team takes a new task and compares it to those it has already completed. If the new feature is twice as difficult as the old one, it gets twice as many points (e.g. 8 instead of 4). Special numbers are used for valuation, often from the Fibonacci sequence (e.g. $1, 2, 3, 5, 8, 13, 21$), to more easily show the big difference between a simple and a very complex task.

The idea of story points came about because counting hours is too unreliable. Estimating time depends on how fast a given programmer works, how many breaks they take and what kind of day they are having. Story points eliminate these problems. By focusing on the objective complexity of the problem rather than the clock, teams plan more realistically and achieve a better, more stable pace of work (known as velocity). Agile created this idea, and Scrum fully adopted it, using it in planning subsequent work periods (called sprints). In practice, story points are a standard tool in both approaches.

Basic principles of estimating story points

In order to properly evaluate tasks using story points, there are a few golden rules to keep in mind. The most important thing is comparison: we always relate a new task to something we have already done (our ‘template’). The valuation must be a joint decision of the entire team, not the idea of one person. What’s more, it’s the difficulty and risk that count, not the time! For this, we use a special, non-linear scale (such as $1, 2, 3, 5, 8$), because the bigger something is, the more uncertain it is. In order for the team to agree on the number of story points, two proven techniques are used:

• Planning poker: this is the most popular ‘card game for estimation’. After discussing the task, everyone secretly chooses a card with their chosen estimate (e.g. 5, 8, 13). The cards are revealed simultaneously. If opinions are strongly divided (e.g. one person gave 3 and another gave 13), the team must discuss where these differences come from until everyone indicates the same, common value.
• T-Shirt sizing: this technique is used when a large number of tasks need to be assessed very quickly, e.g. at the very beginning of a project. Instead of using specific numbers, tasks are assigned sizes like clothes (XS, S, M, L, XL). This allows you to quickly distinguish between what is large and what is small. Only later, when it is time for more detailed project planning, do we convert these ‘T-shirts’ into story points.

How to conduct a story points estimation session?

Instead of describing the session itself, it is important for the project manager or product owner in Scrum to be aware of the most common mistakes that sabotage the credibility and effectiveness of story points. A proper estimation session involves avoiding the following pitfalls:

• Attempting to convert story points into hours: this is the biggest mistake that destroys their meaning. Forcing the team to estimate time under the guise of points leads to unnecessary pressure and underestimation.
• Comparing velocity between teams: velocity (i.e., work pace) is unique to each team. Comparing it generates unhealthy competition and does not provide an accurate picture of performance.
• Using story points as a pressure tool: story points are used for realistic planning, not for control and forcing underestimation. Doing so can undermine trust within the team.
• Overestimating small tasks: spending too much time discussing tasks worth 1 or 2 points is a waste. A better practice is to automatically assign them the lowest value.
• Lack of calibration: the team should agree on and regularly remind themselves what a ‘benchmark’ task means in order to maintain consistency and relativity in all estimates.

Despite these pitfalls, story points are a universal tool in various project contexts. They are used to estimate and prioritise work and to compare tasks. In Scrum, they are a tool that supports Sprint planning and Velocity measurement. Instead of specifying time, the team discusses the relative size of tasks, e.g. saying ‘it seems to be 3 points’, which is more abstract, versatile and allows this measure to be used in both IT and business teams (e.g. marketing).

FlexiProject and story points management

FlexiProject is a tool that allows you to seamlessly introduce and control the entire story point lifecycle, both in Agile and Scrum. The system allows you to directly assign story points to tasks in the Backlog, which is important for prioritising them. Based on the points assigned to tasks and the historical pace of the team’s work (Velocity), FlexiProject will help you plan your sprint schedule by showing how many points the team can realistically complete. The tool automatically tracks and visualises Velocity in subsequent iterations, which is essential for predicting how quickly the work will progress. As part of visualisation and control, advanced burndown/burnup charts are available, which show on an ongoing basis how much work (in points) remains to be done in the Sprint or in the entire project. In addition, the Kanban board allows you to manage tasks with story point estimates, enabling transparent tracking of progress and workflow. With this dashboard, the project manager has control over the current Velocity and the forecast for the entire project, making it easier to meet deadlines.

Story points vs. other estimation method

Story points are a tool that specifically avoids counting time, which is their greatest advantage. When compared to estimating in hours, points are much more stable because they assess the difficulty of the task rather than how fast a given developer works. Hours can easily change (breaks, meetings, fatigue), while the complexity of the task remains the same. Story points are therefore better because we focus on the problem rather than the time pressure. They are also better than Ideal Days, which, although they assume no breaks, are still a unit of time and can easily be confused with real time. However, traditional time estimation (in hours or days) becomes necessary when we need to create a preliminary, fixed budget for a client, we have small, simple service tasks to perform (with zero uncertainty), or we work on projects that require the Waterfall model.

Summary: story points as a tool for better Agile planning?

Story points are a revolution in planning because they are no longer hours, which often fail, but points that measure the actual difficulty, complexity and risk of a task. This stable measure eliminates guesswork. When story points are supported by advanced tools for Agile teams, such as FlexiProject, they become the best way to manage projects effectively, predictably and calmly. In addition, FlexiProject acts as a sprint management tool, as it helps plan Sprints based on the team’s Velocity.