Why and how can you use story points for your project management?

To assess the time needed to complete a project, story points are one of the Scrum tools favoured by development teams.

In fact, this method is an increasingly popular alternative to the traditional man-day estimate, as it doesn't focus on a hypothetical duration, but rather on the amount of effort required.

If this is the first time you've heard of story point, you may feel confused, as this technique is not as intuitive as associating hours with tasks.

Don't panic, today we're going to take you on a tour of story points: we'll explain exactly what they are, go over their advantages and the best way of calculating them.

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Story points: definition

What are story points?

Story points are a unit of measurement used mainly in Scrum agile project management. They are used to estimate the overall workload of teams, so that each sprint or iteration can be planned as effectively as possible.

In concrete terms, a number or value is assigned to each user story (or user scenario) in order to assess the total effort (energy, workload, etc.) to be allocated to its completion. As a result, the story point estimate must take into account all the parameters likely to have an impact on this effort:

• the amount of work to be done ;
• the complexity of the tasks to be carried out
• any risks or uncertainties that could compromise their completion;
• the technical capabilities of the team.

Story point VS man-day

But why not use traditional man-day accounting to determine team workloads?

Quite simply because workloads fluctuate depending on the people involved. For example, a senior developer and a junior developer will not need the same amount of time to carry out a similar task. Story points eliminate this problem, because the estimate no longer depends on the person in charge of the user story.

Ultimately, the story points will help to :

• reducing the risks and grey areas in estimates ;
• improve accuracy, efficiency and flexibility ;
• adapting to people, and therefore creating a climate of trust and goodwill within the project team.

When are story points calculated?

Story points are generally allocated during the definition of user scenarios, more specifically during the refinement backlog.

Upstream of each sprint, the product owner prioritises the future user stories to be worked on. The project team then estimates the effort required to complete them, as it has a limited time (a sprint) to complete the selected scenarios.

☝️ It is important that the whole team works together to determine the story points. This is because each member has his or her own expertise and experience of the specific features of the development to be produced.

How do you get started with story points? The 5 steps to follow

Step 1: Understand the rules of story points

The values and meanings of story points are specific to each project and each organisation.

However, certain rules remain universal:

• Each story, whatever its nature, is allocated a certain number of points.
  
  
• The quantification of the effort required per story point must remain stable for each sprint, and from one story to the next.
  
  
• 2 story points are equivalent to twice the effort of 1 story point. 3 story points is 3 times the effort compared to 1 story point... and so on.
  
  
• It doesn't matter how many points you award. What counts is the ratio.

In the end, story points are a tool for demonstrating the relative effort between each user story and each sprint.

Step 2: Define the value of the story points

As we have seen, the value of story points remains relative. However, we are going to provide you with some basic estimates to give you a frame of reference.

For example, you should know that many teams use the Fibonacci sequence (1, 2, 3, 5, 8, 13, 21, 34, 55, 89, etc.) for their estimates, rather than an ascending linear sequence (1, 2, 3, 4, 5, 6, 7, etc.) or a random sequence of numbers.

💡 What are the advantages of the Fibonacci sequence?

Unlike the linear scale, the intervals between the numbers in this series become wider and wider. As a result, the estimate becomes less accurate as the value increases, which ultimately better reflects the uncertainty inherent in large-scale projects.

Step 3: Analyse the user stories

Once you have determined the values associated with your story points, and before making concrete estimates for your user scenarios, you need to analyse in more detail :

• the nature of the future tasks to be carried out
• their complexity
• the risks and uncertainties that the team may encounter along the way.

Here are a few tips:

• Measure the size of each selected user story as precisely as possible , by calculating the number of tasks and sub-tasks required to complete it.
  
  
• Assess the actual complexity of the tasks. For example, writing 100 standard two-sentence messages is different from creating 10 complete technical descriptions. Even if the latter requires fewer sub-tasks, it will require more effort.
  
  
• Anticipate risks and grey areas as much as possible, to obtain more accurate results. For example, are team members expected to leave? Will they have a major impact on your process?

Step 4: working together to estimate the effort required

Estimating the story points is based on team discussions, often using a card game called Planning Poker, or Scrum Poker.

During a game:

• The team members familiarise themselves with the selected user story and its objectives.
  
  
• They then anonymously estimate the effort required. To do this, each person selects the card with the most appropriate value from their pack of cards.
  
  
• The participants then reveal their cards. If they match, then the final estimate is found. But if they don't, each member of the team argues about his or her choices.
  
  
• Then, after discussion, the estimate is repeated until a consensus is reached.

💡 Your company's history provides valuable data for making a more accurate and credible assessment of story points by comparison. For this reason, if you have already carried out a similar project in the past, use the information relating to your previous performance to make new estimates.

Step 5: Set the final deadlines

Once the number of story points has been defined, it's time to set the timescales for completing the user scenario in question. To do this, determine the speed at which each contributor is capable of executing a single story point.

Let's take the example of a task with a total value of 100 story points. An experienced member of the team will complete a point in 2 hours. A junior member, on the other hand, might take 3 hours. If responsibility for the task is shared equally between these two people, the estimate can be converted into hours in the following way:

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Thanks to this calculation, it is now possible to establish the precise timeframe for the user story.

You now know all the secrets of story points. However, to use this technique correctly, you still need to learn and practise .

But it's worth the effort, because story points offer the opportunity to obtain more accurate and less rigid estimates, and to rethink your approach to project management for the benefit of your team members and the company as a whole.