How to break down product requirements?

Breaking down product requirements can feel like an overwhelming task, especially when dealing with complex features and tight deadlines. However, one of the most valuable lessons I learned from my experiences with Agile methodologies—particularly BDD (Behavior-Driven Development)—is that breaking down requirements systematically is crucial to delivering high-quality software that actually meets user needs. In this post, I want to share some effective techniques for breaking down product requirements using insights I’ve gained through BDD, TDD, and Agile.

The Challenge of Requirement Breakdown

In the early days of my career when I started working for an insurance giant, we transitioned from the Waterfall method to Agile, and we took every aspect of Agile very seriously—100% Agile, complete with Pair Programming, TDD, BDD, and Scrum. It was an intense shift, and the level of process adherence was challenging for everyone. Despite the difficulties, one major benefit was that it taught us how to effectively break down requirements into manageable pieces.

Initially, breaking down product requirements felt like a cumbersome task. Pair Programming sometimes felt awkward, TDD required writing tests before we could even touch the actual code, and BDD had us writing requirements in Gherkin syntax—using Cucumber to test it all. I remember thinking, “I’m not in the mood for a salad—I just want to code!” The rigidity of these processes often overshadowed productivity. However, looking back, the structure it provided was invaluable in helping me understand how to take a complex requirement and break it into smaller, actionable tasks.

The BDD Approach to Requirements

Despite the growing pains, BDD eventually taught me the value of capturing requirements in a way that is clear, testable, and linked to user needs. BDD focuses on understanding the behavior of the system from the user’s perspective. The goal is to create shared understanding between developers, product owners, and stakeholders, and write requirements that everyone can understand.

Here’s how BDD can help break down product requirements more effectively:

Write User Stories in Simple Language
- In BDD, requirements are written in the form of user stories. These stories follow the format: “As a [user], I want to [goal], so that [reason].” This approach forces you to consider the end-user’s needs and define the goal clearly.
Example: “As a student, I want to submit my assignments online, so that I can get feedback from my teacher quickly.”

This structure ensures that you keep the user at the center of every requirement and helps to ensure everyone is on the same page about what the feature should accomplish.
Define Acceptance Criteria Using Gherkin
- After writing the user story, the next step is to define the acceptance criteria. This is where Gherkin syntax comes in handy, allowing you to describe the behavior of the feature in a consistent, structured way.
Example:
```
Scenario: Submit an assignment
  Given the student is logged in
  When the student clicks on "Submit Assignment"
  Then the assignment should be successfully uploaded
  And a confirmation message should be displayed
```
Writing acceptance criteria this way helps in breaking down the feature into individual, testable behaviors. Each step corresponds to a specific action or outcome, making it easy for developers and testers to understand what exactly needs to be implemented.
Collaborate with Stakeholders
- Breaking down requirements should never be a solitary activity. BDD emphasizes collaboration, and that’s one of the keys to success. Gather feedback from product owners, designers, and stakeholders to ensure everyone has a shared understanding of the requirements.
Identify Positive and Negative Scenarios
- Don’t just focus on the happy path—consider edge cases and potential failure points. For example, what happens if a student tries to submit an assignment without attaching a file? Thinking through these scenarios will help break down the requirements more thoroughly and lead to better test coverage.
Example:
```
Scenario: Attempt to submit an assignment without a file
  Given the student is on the assignment submission form
  When the student tries to submit without attaching a file
  Then an error message should be displayed
  And the assignment should not be submitted
```

My Approach: Balancing BDD with Practicality

When I moved away from the rigid implementation of these methodologies, I found a balance that worked for me. Today, I use a more flexible approach inspired by BDD principles. Instead of always sticking to formal Gherkin scenarios, I focus on breaking down requirements in a way that ensures clarity and aligns with the team’s workflow.

Requirement Breakdown Without Overhead: I focus on ensuring that requirements are clear and can easily translate into unit tests or functional tests. I document these requirements in a way that is accessible to both technical and non-technical team members.
Focus on Acceptance Criteria: Writing detailed acceptance criteria helps align expectations. I use simple language and concrete examples to describe what the feature should do, both in positive and negative scenarios.
Iterative Improvement: Often, I start coding with a high-level understanding of the requirements. As the implementation progresses, I iterate on the tests and the requirements, refining them as I gain more insights into the system and its challenges.

Practical Example: Breaking Down an Assignment Creation Feature

Let’s say you need to implement an assignment creation feature for an educational platform. Here’s how I would break down the requirements:

User Story:
- “As a teacher, I want to create, edit, and view assignments for my students, so that I can manage their progress effectively.”
Acceptance Criteria:
- Creating an Assignment:
  - Given a teacher is logged in, when they click “Create Assignment,” an assignment creation form should be displayed.
  - The teacher should be able to enter assignment details, including title, description, and due date.
- Editing an Assignment:
  - Given an assignment exists, when the teacher clicks “Edit,” they should be able to modify the assignment details.
  - Changes should be saved, and the teacher should see a confirmation message.
- Viewing Assignments:
  - Given assignments have been created, when the teacher navigates to the assignments page, they should see a list of all created assignments, including titles and due dates.
Positive and Negative Scenarios:
- Positive: Creating an assignment with valid details should save it successfully.
- Negative: Attempting to save an assignment without a title should display an error.
- Edge Case: Attempting to set a due date in the past should display a warning and prevent saving.

Conclusion

Breaking down product requirements is a crucial skill that leads to better, more maintainable software. BDD is a powerful tool that can help bring clarity to the process, but it doesn’t have to be rigid or overly formal. By focusing on user stories, defining clear acceptance criteria, and collaborating closely with stakeholders, you can create requirements that drive quality and meet user expectations.

Remember, the goal isn’t to enforce a strict process for the sake of process—it’s to build a shared understanding and deliver features that work as intended. The methods and tools you use to break down requirements should ultimately make life easier for both you and your team.