Structuring Use Cases: A Comprehensive Guide to Defining User Goals, Actors, and Outcomes

What is Use Case Modeling

Use cases are an important tool in software development to help define the system requirements and ensure that the end product meets the user’s needs. A well-structured use case describes the steps a user takes to accomplish a specific goal, and it provides a clear understanding of what the system needs to do to support that goal. In this guide, we will explore how to structure use cases with a focus on the goals, why they are important, and how to create effective use cases.

Goals of Use Cases

The primary goal of use cases is to capture the user’s requirements and provide a blueprint for the development team to follow. This helps to ensure that the system meets the user’s needs and is designed with a user-centric approach. A use case should clearly define the following:

• The goal that the user is trying to accomplish
• The steps involved in achieving the goal
• The actors involved in the process (e.g., users, systems, external entities)
• The expected outcome of the process

By structuring use cases with these elements, it becomes easier to identify potential problems, anticipate user needs, and design a system that meets those needs.

Why are Use Cases Important?

Use cases are important for several reasons, including:

1. Clarity – Use cases provide a clear and concise understanding of the user’s goals and the steps involved in achieving them. This helps to ensure that everyone involved in the development process has a shared understanding of what the system needs to do.
2. User-centric – Use cases provide a user-centric approach to software development. By focusing on the user’s needs and goals, the system can be designed to meet those needs, resulting in a more usable and effective system.
3. Communication – Use cases provide a common language that can be used to communicate requirements and expectations between stakeholders, including developers, designers, and users.
4. Requirements Validation – Use cases provide a way to validate requirements by testing them against user goals and scenarios. This helps to identify potential problems early in the development process and make necessary adjustments.

How to Structure Use Cases

Use cases can be structured in many ways, but they should always include the key elements mentioned earlier. Here is a general approach for structuring use cases:

1. Identify the user goal – Start by identifying the goal that the user is trying to achieve. This should be a clear and concise statement that captures the user’s objective.
2. Identify the actors – Next, identify the actors involved in the process. This could include users, systems, and external entities that interact with the system.
3. Define the steps – Define the steps involved in achieving the goal. This should be a detailed description of the process, including any inputs and outputs.
4. Identify alternate paths – Identify any alternate paths or exceptions that could occur during the process. This could include errors, unexpected inputs, or other scenarios that could impact the outcome.
5. Define the outcome – Finally, define the expected outcome of the process. This should be a clear description of what the user should expect to see or experience when the process is complete.

It is also important to remember that use cases should be written in plain language that is easy for everyone to understand. Use simple, straightforward language and avoid technical jargon or complex descriptions.

Example: Making a Purchase on an E-commerce Website

1. Identify the user goal – The user wants to purchase a product on an e-commerce website.
2. Identify the actors – The actors involved in the process are the user and the e-commerce website.
3. Define the steps – The steps involved in making a purchase on an e-commerce website are:
   • a. The user browses the website to find the desired product.
   • b. The user adds the product to their shopping cart.
   • c. The user reviews their shopping cart and proceeds to checkout.
   • d. The user enters their shipping and payment information.
   • e. The user reviews their order and confirms the purchase.
   • f. The website sends an order confirmation to the user.
4. Identify alternate paths – Some alternate paths or exceptions that could occur during the process are:
   • a. The product is out of stock, and the user is notified that it cannot be added to their cart.
   • b. The user enters incorrect or incomplete shipping or payment information, and the website displays an error message.
   • c. The user cancels the purchase before confirming the order.
5. Define the outcome – The expected outcome of the process is that the user successfully completes the purchase, and the website sends an order confirmation to the user.

Elaborating a use case with a Use Case Description

Title: Making a Purchase on an E-commerce Website

Goal: The user wants to purchase a product on an e-commerce website.

Actors: User, e-commerce website.

Preconditions: User is on the e-commerce website and has identified the desired product.

Main Flow:

1. The user browses the website to find the desired product.
2. The user adds the product to their shopping cart.
3. The user reviews their shopping cart and proceeds to checkout.
4. The user enters their shipping and payment information.
5. The user reviews their order and confirms the purchase.
6. The website sends an order confirmation to the user.

Alternate Flows:

1. If the product is out of stock, the user is notified that it cannot be added to their cart.
2. If the user enters incorrect or incomplete shipping or payment information, the website displays an error message.
3. If the user cancels the purchase before confirming the order, the process ends.

Postconditions: The user has successfully completed the purchase, and the website sends an order confirmation to the user.

By consolidating the information and steps into a proper use case description, it becomes easier to communicate and document the requirements and expectations of the system. This use case can then be used as a reference throughout the development process to ensure that the system meets the user’s needs and goals.

Conclusion

In conclusion, structuring use cases with a focus on the goals, why they are important, and how to create effective use cases is essential to ensuring that the system meets the user’s needs. By providing a clear and concise understanding of the user’s goals, the system can be designed with a user-centric approach, resulting in a more usable and effective system. With the right approach and attention to detail, use cases can be a powerful tool for software development teams to ensure that they are delivering a high-quality product that meets user expectations.