HomeAgileUse Case vs. User Stories: What's the Difference?

Use Case vs. User Stories: What’s the Difference?

These days, when using different software development methodologies, it’s common for newcomers, even veterans, to be confused over the many similar-sounding terms.

Sometimes the confusion is not due to the similar-sounding names but that the terms seemingly refer to the same thing or serve apparently similar purposes. Hence, it’s only forgivable if you get confused from time to time. One such often confused pair of terms is Use Case’ vs User Story.

In this article, we will explore what the terms mean and highlight some key differences between the two. Lastly, you will get a real example of a use case vs. a user story.

Let’s begin.

Is Use Case and User Story Interchangeable?

I often hear people asking whether the terms use case and user story can be used interchangeably. Unfortunately, the short answer is no!

User cases and user stories are so different that Alistair Cockburn, co-author of the Agile Manifesto, said,

A user story is to a use case as a gazelle is to a gazebo.

Alistair Cockburn

He was basically saying that just because ‘use case’ and ‘user story’ share a few letters doesn’t imply that they mean the same thing!

However, although use cases and user stories are very different, they still share some similarities; otherwise, people wouldn’t get confused. We will also explore these below.

After several years of debating this question and seeing both in use, I now think they have nothing in common other than their first three letters.

Alistair Coburn

What is a Use Case? 

Use cases as a concept were first introduced to the public in 1987 by Ivar Jacobson, a Swedish-American computer scientist and software engineer. 

A use case is a complex and detailed method used to capture a user’s requirement. Use cases describe the step-by-step interactions between a system and a user or another system or device. 

They detail the various paths actors on the system (e.g., users, systems, or devices) may interact with the system to achieve their goal. It covers the user’s interaction and includes the ideal system response to each user action or request. Hence, a use case covers the whole customer’s experience when using a system’s feature to achieve their goal.

Use cases are made up of several components, which help create a format or template that anyone can use to craft their use cases.

The common use case format or template includes the following seven components:

  1. Use Case Name.
  2. Description.
  3. Pre-condition.
  4. Post-condition.
  5. Basic Path.
  6. Alternative Path(s).
  7. Exception Paths.

The above components will help you plan out a more effective and appropriate use case, AKA use scenario.

Advantages of Use Cases.

  1. Provide Detailed Guidelines for Developers: Developers don’t have to spend as much time planning out and organizing the tasks or scope of the work to be done. Hence, they can quickly start the development process without having additional meetings.
  2. Accounts for alternative paths: People are different, and so is the way they may use the same product. Hence, planning for alternative approaches other people may use helps cater to wider audiences and shows inclusivity.
  3. Very Detailed and Reduce future planning: Use cases are so detailed that the planning members don’t have to waste time frequently re-planning for the same job.
  4. The format enables thorough planning: The format used for use cases ensures that you don’t forget anything during your planning session. In addition, it provides an easy-to-follow template that helps to streamline planning sessions.

What is a User Story?

Kent Beck, the creator of extreme programming, coined the term, User Story. His idea was that use cases were too complex and technical. Therefore, the business departments of an organization were unable to participate during discussions. Here’s what he said:

My purpose is to maintain a balance of political power between business and development. Use cases as I have seen them used are complex and formal enough that business doesn’t want to touch them. This leads to development asking all the questions and writing down all the answers and taking responsibility for the resulting corpus. Business is reduced to sitting on the other side of the table and pointing.

Kent Beck

I want a very different dynamic. I want business to feel ownership of and take responsibility for the care and maintenance of “the requirements”. I want business to feel comfortable making priority decisions about the requirements. I want business to feel free to add new requirements, and add new detail to existing requirements, as development progresses

Kent Beck

So what is a user story?

In simple terms, a user story is a brief narrative that describes a feature the user needs to achieve their goals (business or otherwise). It’s written from the perspective of the end-user. In other words, a user story is the customer’s first-person narrative describing their situation, need, and goal. User stories are most widely used during the implementation of Agile development methodologies such as Scrum.

Each user story focuses on one key value or features the customer/user needs from your service or product. 

Mike Cohn, an expert ScrumMaster and educator, popularized the standard format or template used to craft user stories. Here it is:

  • As an (Actor/User/Customer)
  • I want (Functionality)
  • So that (Why / Achievement / Benefit) 

As you can see, a user story must be brief and simple to understand. It should not include too much technical jargon. In fact, it should be a high-level abstraction that non-technical personnel can understand and therefore contribute during planning discussions.

A user story should only address the Who, What, and Why of the user’s requirement without straying into the How. The How is up to the development team to figure out because, in Agile, development teams are self-managing and self-organizing. Suppose the user story already describes the How. In that case, the development team will lose the room they need to maneuver and build their best value product.

To conclude, a user story is a method used in Agile to define or collect user requirements. It’s written in the language a customer would use without any technical or hard-to-understand concepts. It’s accompanied by other supporting components such as the Acceptance Criteria, which helps developers assess their product’s completion. 

Advantages of User Stories

  1. Simple to Understand: User stories are simple by nature as they use natural language without any technical jargon. Therefore, almost anyone can quickly understand a user story even if they have no development background.
  2. User-Centric: User stories prioritize the customer’s narrative and needs. Therefore, it’s more likely that developers can deliver a product that matches their customer’s requirements.
  3. Improves Collaboration: Because user stories are easy to understand, all involved parties/department within the organization can lend their expertise towards achieving the best product.
  4. Easier to Craft: User stories are shorter than use cases; hence, they are much faster and less stressful to write.
  5. Easy to organize and arrange execution order: Because user stories can be understood quickly, it’s much easier to rearrange and prioritize their order during backlog grooming sessions.

Use Case vs. User Story

Use cases have been around for a while. On the other hand, user stories only became popular due to the increasing popularity of Agile in recent years. Why? Well, user stories are more suited to Agile principles than use cases. Although some analysts suggest using use cases and user stories together, most companies still prefer user stories to use cases because they are faster to create and much shorter.

However, user stories have their fair share of problems, as highlighted by Alistair Cockburn. He says the companies who consult with him often have three main issues with user stories, which are:

  • Lack of context (what’s the most significant goal).
  • Lack of exhaustive detail relating to a goal.
  • Lack of a mechanism to foresee upcoming work.

Similarities

Use cases and user stories have some similarities that might confuse people.

For example, use cases and user stories both have a measurement they use to assess complete work. In user stories, we use acceptance criteria, while in use cases, we use the post-condition. In addition, use cases also have a pre-condition which can be equated to the definition of ready in user stories.

Another similarity between the two terms is that they both attempt to describe a single user requirement.

Differences

Methodology: Use cases are often used in Waterfall Development methodologies because it depends upon exhaustive requirement gathering. In contrast, User stories are most used in Agile Development Methodologies because they defer many details, enabling quick adaptations to rapidly changing environments.

Level of Detail: Use cases are very detailed. They have almost every component that may affect the work on the user’s requirement. On the other hand, user stories aim to be brief. Hence, they skip a lot of details.

Time Consumed: The time taken to plan for and craft a good use case is longer than what it takes to plan and craft a user story.

Level of Formality: Use cases are more formal documents that list the various steps a customer can take on the system. In comparison, a user story is written in friendlier natural language, which is far easier to understand.

Customer Referred to In what person: Often, the customer is referred to in the third person in use cases. In comparison, user stories are written with the customer being the first party.

Format/ Components: User stories only have three components that need to be addressed, which are Who, What, and Why. On the other side, use cases have seven components that need to be addressed.

Precision Level: Use cases are more precise when formalizing all the details of a user requirement. In contrast, user stories only give an example of expected results. Furthermore, user stories don’t even address alternative usage paths.

What is captured: User stories mainly capture the who, the functionality, and output of a system, while use cases capture much much more.

As far as I can tell, a UseCase and a UserStory have next to nothing in common. About as different as you can get for having names so similar. It should be called Abdefind and Zytyopy to make that clearer. — Alistair Cockburn

 Also Read: Best Testing Practices in Agile: The 4 Steps

Examples: Use Case vs. User Story

We will create a user story and a use case for a situation where you will be working with a client that owns and manages a massage parlor called Nirvana.

The client wants an app that allows their customers to book an appointment on their mobile phone.

Example of a User Story

We are going to use our user story template, which is:

  • As an (Actor/User/Customer);
  • I want (Functionality)
  • So that (Why / Achievement / Benefit) 

So our user story becomes:

  • As a Customer
  • I want only to see the time slots when my selected masseuse is available.
  • So that I can make my appointment for a massage session

User stories need an acceptance criteria which uses a template of:

  • Given (context or circumstance)
  • When (event)
  • Then (result or outcome)

So our acceptance criteria becomes:

  • Given I am a customer and I am logged into the Nirvana mobile app.
  • When I click on “Book a Session” after selecting my preferred date.
  • Then I can only see the time slots when my masseuse is not booked. 

Example of a Use Case

Use Case Name.Only display available time slots for my masseuse.
Description.A customer should be only shown time slots when their selected masseuse is available for booking.
ActorCustomer
Pre-condition.The customer should have installed and logged into their Nirvana mobile app.
Post-condition.The customer should get a confirmation SMS or email with their booking’s details.
Basic Path
CustomerSystem Response
Click on ‘Book a Session’ buttonSystem displays the fields for selecting the masseuse and preferred date.
Select the masseuse and dateSystem validates and then only displays the available timeslots.
Select a timeslotCustomer receives a confirmation message with their booking’s details.
Alternative Path
Customer ResponseSystem Response
Click on ‘Book a Session’ buttonSystem displays the fields for selecting the masseuse and preferred date.
Select the masseuse and dateSystem validates and displays, “The selected date for the chosen masseuse is fully booked and not available.”
Selects a different masseuse or dateSystem validates again and displays the available timeslots.
Select a timeslotCustomer receives a confirmation message with their booking’s details.
Exception Paths.
Customer ResponseSystem Response
Click on ‘Book a Session’ buttonSystem displays the fields for selecting the masseuse and preferred date.
Select the masseuse and dateSystem validates and displays, “The selected date for the chosen masseuse is fully booked and not available.”
Clicks on Exit or HomeSystem should close the Nirvana app.

Conclusion

To conclude, user stories are clearly much shorter than use cases. Consequently, they are much easier and faster to use in your planning during Agile. On the other hand, use cases are longer and more thorough; therefore, they lessen the burden of future planning as all the possible outcomes are already accounted for. 

Use cases are more common in sequential development methodologies like the Waterfall model. This is because sequential methodologies depend on thorough requirement analysis and gathering before development. In contrast, iterative methodologies like Agile rely much more on user feedback and ongoing situations than comprehensive requirement analysis. Hence, you will find user stories in Agile.

A case for using both use cases and user stories is increasingly being made. However, the value of such a practice still needs to be further proven. 

That’s all we have on use case vs. user story.

Thanks for reading! 

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