User Stories and Product Backlog Items (PBIs) are work items used to manage and track the development of specific features or functionalities within a software project, typically within an Agile framework.

However, they each serve slightly different purposes.

Let’s explore the key differences, as well as some of the advantages and disadvantages of each:

User Stories

As the name suggests, User Stories are primarily focused on the “User” - the end-users or customers that your product is designed to serve. Specifically, they are “customer-centric”, describing the functionality from the perspective of the user, emphasizing the “who”, “what”, and “why."

Role-Based

User Stories are written in a way that focuses on specific roles or personas who will use the feature. Typically, User Stories include a defining statement that adheres to a standard format: "As a [User], I want [Goal] so that [Benefit]”.

Informal

While they adhere to a standard format, User Stories are often written in a more informal and narrative style, making them user-friendly and accessible to non-technical stakeholders. The inclusion of comprehensive technical information is important and definitely encouraged, but technical information can be added later by the respective technical teams once they’ve assessed and understood the requirement(s) from the user’s perspective.

Advantages

• Promotes customer-centric thinking.
• Easily understandable by non-technical team members and stakeholders.
• Encourages conversations and collaboration with users and product owners.
• Somewhat easier to prioritize as each story is assessed based on its perceived value to the end-users and business objectives.
• Estimating User Stories is often easier due to their smaller size and more defined scope. Techniques like story points or t-shirt sizing are commonly used.

Disadvantages

• May lack technical details, making it challenging for development teams to estimate and plan.
• Can be overly focused on end-user needs at the expense of technical concerns.

Product Backlog Items

Product Backlog Items (PBIs) represent a much broader range of work items, including user stories, as well as technical tasks, bugs, infrastructure changes, and more. They are not necessarily user-centric and can cover any work related to the product.

Technical Details

As a rule, PBIs tend to focus much more on technical details and specifications, making them more informative for development teams. They should always include acceptance criteria and the required additional technical context but don’t necessarily adopt the narrative, user-centric approach of User Stories. Typically, PBIs are defined through a description of the Product (or function, or feature) instead of the end-user.

Structured

PBIs are often more structured and can be categorized into different types. These types can include bug fixes, enhancements, technical tasks, design and prototypes, documentation, UAT, integration(s), and compliance requirements.

Advantages

• Allows for a more comprehensive view of work items, including technical tasks and bugs.
• Provides a platform for including technical details and specifications.
• Facilitates better planning and estimation for the development team.
• PBIs can be viewed by a wider audience, including developers, testers, architects, and others involved in the development process. They encompass not just end-user needs but various aspects of project management.

Disadvantages

• May be less accessible to non-technical stakeholders due to the technical details.
• Can potentially lead to a disconnect between technical and business-focused team members.
• Estimating PBIs can be more challenging, especially when they include a mix of User Stories, technical tasks, and other work items. Different estimation techniques may be needed.
• Prioritization of PBIs can be more complex since it involves a broader range of work items and may require additional considerations such as overall business value, dependencies, and effort required.

Acceptance Criteria

Regardless of whether your project is best served with User Stories or Product Backlog Items, documenting the Acceptance Criteria is still a critical consideration.

Typically more detailed and descriptive than a simple checklist, a robust Acceptance Criteria will outline the specific features, functions, and performance standards that the product or deliverable must meet.

Acceptance criteria, when written for either User Stories or PBIs, should include:

• Specific functional requirements.
• Performance metrics.
• Use cases.
• Test cases and scenarios.
• Regulatory and compliance requirements.
• Constraints and limitations.

In both cases, it is the Acceptance Criteria that will be used to define the “Definition of Done”, and allow the PM to close the Task and the dev team to move on to the next User Story or PBI as required.

Summary

Overall, the choice between User Stories and PBIs often depends on the specific needs of your team and the nature of your project.

User Stories are ideal when you want to emphasize user needs and encourage collaboration with non-technical stakeholders.

On the other hand, PBIs offer a more comprehensive approach, allowing you to track various types of work items and is the ideal solution when you need to include significant technical detail.

Either work item approach can be effective - it’s up to you as the Product Owner or Project Manager to find a balance that best serves your team and is best aligned with your project goals.