User stories are a fundamental unit of work in agile methodologies, capturing functionality from the end user's perspective. The INVEST criteria provide a framework for creating high-quality user stories that drive effective development and deliver value to users.
User stories should be self-contained and independent of other stories. This independence allows for flexible prioritization and implementation without complex dependencies.
"As a user, I want to create an account with email verification."
"As a user, I want to reset my password using email confirmation."
These stories can be implemented in any order as they're independent of each other.
"As a user, I want to add items to my shopping cart."
"As a user, I want to view items in my shopping cart."
The second story depends on the first, creating an unnecessary dependency.
When dependencies are unavoidable, consider combining related stories or breaking them down differently to maintain independence.
User stories should be flexible and open to discussion. They capture the essence of the requirement without prescribing a specific solution, allowing for collaboration and refinement.
"As a user, I want to be notified of important account activities."
This leaves room for discussion about notification methods and what constitutes "important."
"As a user, I want to receive SMS and email notifications with specific formatting using template XYZ when any account change occurs."
This is too prescriptive and leaves no room for discussion or alternatives.
Keep implementation details in acceptance criteria rather than the story itself, allowing for flexibility in the solution approach.
Each user story must deliver clear value to the end user or stakeholder. The value should be evident and align with business objectives.
"As a marketing manager, I want to see conversion rates by campaign so that I can optimize marketing spend."
Clear business value: improved marketing efficiency and ROI.
"As a developer, I want to refactor the authentication module using the latest framework."
Technical task without clear user value should be part of technical debt management.
Always include "so that..." to explicitly state the value proposition of the story.
Development teams should be able to estimate the effort required to implement the story. This requires sufficient detail and understanding.
"As a user, I want to filter products by category, price range, and availability."
Clear scope with specific filter criteria makes estimation possible.
"As a user, I want the application to be fast."
Too vague to estimate meaningfully.
Include acceptance criteria that help bound the scope and clarify expectations.
Stories should be small enough to be completed within a single sprint. Smaller stories reduce risk and enable better planning and tracking.
"As a user, I want to update my profile picture."
Focused scope that can be completed quickly.
"As a user, I want a complete social networking feature set."
Too large and should be broken down into smaller stories.
If a story takes more than a few days, consider breaking it down into smaller, valuable increments.
Stories must be written so that they can be tested to verify completion. Clear acceptance criteria enable effective testing.
"As a user, I want to search for products by name, receiving results within 2 seconds for up to 1000 items."
Contains specific, testable criteria.
"As a user, I want the system to be user-friendly."
Subjective and not testable without specific criteria.
Include specific, measurable acceptance criteria that can be verified through automated or manual testing.
When reviewing user stories, ensure they meet these requirements: