Why and how to use story points for project management?

Story points are one of the Scrum tools preferred by development teams for estimating the time needed to complete a project.

In fact, this method is an increasingly popular alternative to the traditional man-day estimate, since 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 be feeling 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, look at their advantages and explain how best to calculate 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 a team's overall workload, in order to best plan each sprint or iteration.

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

• the amount of work to be done ;
• the complexity of the tasks to be performed
• 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 workload?

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

Ultimately, story points are beneficial for :

• reduce risks and grey areas in estimates ;
• increase precision, efficiency and flexibility ;
• adapting to people, and thus creating a climate of trust and goodwill within the project team.

When are story points calculated?

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

Upstream of each sprint, the product owner prioritizes 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 finish the selected scenarios.

☝️ It's important that the whole team works together to determine the story points. After all, each team member has his or her own expertise and experience in the specifics of the development to be produced.

How do you get started with story points? 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 organization.

However, certain rules remain universal:

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

Ultimately, story points are a tool to demonstrate the relative effort between each user story and each sprint.

Step 2: Define the value of story points

As we've seen, the value of story points remains relative. However, we're 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 precise as the value increases, which ultimately better reflects the uncertainty inherent in large-scale projects.

Step 3: Analyze user stories

Once you've determined the values associated with your story points, and before making concrete estimates for your user scenarios, it's time to analyze in greater detail :

• the nature of the future tasks to be performed,
• their complexity,
• the risks and uncertainties 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 mobilize more effort.
  
  
• Anticipate risks and grey areas as far as possible, so as to obtain more precise results. For example, are team members expected to leave? Will they have a major impact on your process?

Step 4: work together to estimate the effort required

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

During a game :

• Collaborators familiarize themselves with the selected user story and its objectives.
  
  
• Then, anonymously, they estimate the effort required. To do this, each player selects the card with the most appropriate value from his or her deck of cards.
  
  
• Participants then reveal their cards. If they match, then the final estimate is found. But if they don't, each team member 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 story points assessment by comparison. Therefore, if you've already completed a similar project in the past, use information about your previous performance to make new estimates.

Step 5: Set final deadlines

Once you've defined the number of story points, it's time to set the deadlines for 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 team member will complete a point in 2 hours. A junior member, on the other hand, may take 3 hours. If the task's responsibilities are divided equally between these two collaborators, then the estimate can be converted into hours in this way:

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Thanks to this calculation, it's now possible to accurately establish the user story's lead time.

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

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