Everything (you need to know) about User Stories

User story in Agile Software Development

What is a User Story?

In the context of Agile Methodology

A User Story comprises narrative texts that describe an interaction of the user and the system, focusing on the value a user gains from the system.

A true user story is a metaphor for the work being done. It is not a highly documented requirement, but rather a reminder to collaborate about the topic of the user story.

User stories aren’t agile in and of themselves. Instead, their underlying agile values—collaboration and just-in-time definition—make user stories a good agile tool.

In Agile Software Development

User stories are used with agile software development methodologies as the basis for defining the functions a business system must provide, and to facilitate requirements management.

In Product Management

A user story is a short, simple description of a feature told from the perspective of the person who desires the new capability, usually a user or customer of the system.

Classic User Story structure:

As a <role>, I want <goal/desire> so that <benefit>

Example: As a customer, I want to be able to create an account, so that I can see my order.

Improved version:

As a <specific user/persona/role>, I want <desired feature/issue that needs to be solved>, so that <benefit from implementing the feature>” + Acceptance Criteria

Example: As a new customer, I want to be able to register online, so I can create an account quickly

Acceptance Criteria:

A user cannot submit a form without completing all the mandatory fields.
Information from the form is stored in the registrations database.
Protection against spam is working.
An acknowledgment email is sent to the user after submitting the form.

Guidelines for User stories (3C guidelines):

Card: User stories are traditionally written on index cards or sticky notes, in short form. User narratives further explain these cards. Thus the main intention is to describe the user story in short form to allow common understanding of the user need among all stakeholders.
Conversation: User stories shift the focus from writing about features to discussing them. In fact, these discussions are more important than whatever text is written.
Confirmation: Acceptance tests confirm that the story was delivered correctly.

What makes a good User Story:

A good user story uses the “INVEST” model:

Independent: Reduced dependencies = easier to plan
Negotiable: Details added via collaboration
Valuable: Provides value to the customer
Estimable: Too big or too vague = not estimable
Small: Can be done in less than a week by the team
Testable: Good acceptance criteria

Who writes User Stories?

Customer or Business user
Product owner
Team member

Essentially, any stakeholder can write user stories to assign the functions a software system or a product must provide.

Who maintains User Stories?

Product owner

The process of creating a User Story?

In consultation with the customer or product owner, the team divides up the work to be done into functional increments called "user stories".

Tools

Index card
Sticky note
Project management software such as JIRA, Basecamp, Trello, Asana, Rally software etc.

Techniques

User stories are sketched out by the product owner, then the full product team collectively decide the more detailed requirements.

More information about User Stories:

User stories are one of the primary high-level development artifacts for Scrum and Extreme Programming (XP) project teams.
A User Story is part of an agile approach that helps shift the focus from writing about requirements to talking about them. All agile user stories include a written sentence or two and, more importantly, a series of conversations about the desired functionality.
A user story is a tool used to capture a simplified description of a feature or a requirement from an end user perspective.
User stories are a simple, concise way to communicate how a user or customer interacts with a product.
A user story describes the type of user, what they want and why. It captures the "who", "what" and "why" of a requirement in a simple, concise way, often limited in detail by what can be hand-written on a small paper index card.
A user story is a description consisting of one or more sentences in the everyday or business language of the end user or user of a system that captures what a user does or needs to do as part of his or her job function.
A user story is a very high-level definition of a requirement, containing just enough information so that the developers can produce a reasonable estimate of the effort to implement it.
A user story encapsulates the action of one function making it possible for software developers to create a vertical slice of their work.
The goal of a user story is to deliver a particular value back to the customer. Note that "customers" don't have to be external end users in the traditional sense: they can also be internal customers or colleagues within your organization who depend on your team.
Each user story is expected to yield, once implemented, a contribution to the value of the overall product, irrespective of the order of implementation; these and other assumptions as to the nature of user stories are captured by the INVEST formula.
In an agile framework, a user story is the smallest units of work that should be completed in one sprint. Smaller than that it’s a task, more than week(s) of work is Epic or Theme.
In JIRA Agile, a story is represented as an issue, and individual tasks within the story are represented as sub-tasks.

References:

New to User Stories? - www.scrumalliance.org/community/articles/2010/april/new-to-user-stories
User Story from Wikipedia - en.wikipedia.org/wiki/User_story
Writing User Stories, Examples and Templates In Agile Methodologies - http://www.yodiz.com/blog/writing-user-stories-examples-and-templates-in-agile-methodologies/
User Stories - https://www.mountaingoatsoftware.com/agile/user-stories
Agile User Stories - https://www.scrumalliance.org/community/articles/2013/september/agile-user-stories