Introduction to User Stories

Mike Cohn
Norwegian Developer’s Conference
6 June 2012
User Stories
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© Copyright Mountain Goat Software
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What problem do stories address?
Software requirements is a communication
problem
Those who want
the software must
communicate with
those who will
build it
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Balance is critical
If either side dominates, the business loses
If the business side dominates…
…functionality and dates are mandated with little
regard for reality or whether the developers
understand the requirements
If the developers dominate…
…technical jargon replaces the language
of the business and developers lose the opportunity to
learn from listening
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Resource allocation
We need a way of
working together so
that resource allocation
becomes a shared
problem
Project fails when the
problem of resource
allocation falls too far to
one side
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Responsibility for resource allocation
If developers are responsible…
May trade quality for additional
features
May only partially implement a
feature
May solely make decisions that
should involve the business
If the business is responsible…
Lengthy upfront requirements
negotiation and signoff
Features are progressively
dropped as the deadline nears
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Imperfect schedules
We cannot perfectly predict a software
schedule
As users see the software, they come up with
new ideas
Too many intangibles
Developers have a notoriously hard time
estimating
If we can’t perfectly predict a schedule, we
can’t perfectly say what will be delivered
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This is where
user stories
come in
So what do we do?
…but do it often
We make decisions based
on the information we
have
…we spread decision-
making across the project
Rather than making one
all-encompassing set of
decisions
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Agenda
What stories are
Writing user stories
Why user stories
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Three Cs
Stories are traditionally
written on note cards.
Cards may be annotated with
estimates, notes, etc.
Card Details behind the story come
out during conversations with
product owner
Conversation
story was coded correctly
Conﬁrmation
Source: XP Magazine 8/30/01, Ron Jeﬀries.
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As a user, I want to
reserve a hotel room.
As a user, I want to
cancel a reservation.
As a vacation traveler,
I want to see photos of
the hotels.
As a frequent ﬂyer, I
want to rebook a past trip
so that I save time
booking trips I take often.
Samples from a travel website
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Where are the details?
As a user, I can cancel a reservation.
Does the user get a full or partial refund?
Is the refund to her credit card or is it site credit?
How far ahead must the reservation be cancelled?
Is that the same for all hotels?
For all site visitors? Can frequent travelers cancel later?
Is a conﬁrmation provided to the user?
How?
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Details as conditions of satisfaction
As a user, I can
Verify that a premium member can
cancel the same day without a fee.
Verify that a non-premium member is
charged 10% for a same-day cancellation.
Verify that an email conﬁrmation is sent.
Verify that the hotel is notiﬁed of any
cancellation.
• The product owner’s
conditions of satisfaction
can be added to a story
• These are essentially
tests
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Details added in smaller sub-stories
As a user, I can
As a site visitor, I am
emailed a conﬁrmation of
any cancelled
reservation.
As a non-premium
member, I can cancel up
to 24 hours in advance.
As a premium site
member, I can cancel a
reservation up to the
last minute.
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Techniques can be combined
These approaches are not mutually
exclusive
Write stories at an appropriate level
By the time it’s implemented, each story
will have conditions of satisfaction
associated with it
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© Copyright Mountain Goat Software®
The product backlog iceberg
Priority
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Some additional useful terms
Epic
A large user
story
Theme
A collection of
related user
stories
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An example
As a VP Marketing, I want to
select the timeframe to use
when reviewing the
performance of past
promotional campaigns, so
that …
As a VP Marketing, I can
select which type of
campaigns (direct mail, TV,
email, radio, etc.) to include
when reviewing the
performance of past …
As a VP Marketing, I want
to review the performance
of historical promotional
campaigns so that I can
identify and repeat
proﬁtable ones.
Clearly an epic
Epics???
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to see information on
direct mailings when
reviewing historical
campaigns.
to see information on TV
ads when reviewing
historical campaigns.
to see information on
email ads when reviewing
historical campaigns.
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Agenda
What stories are
Why user stories
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Logging in
•See how many user stories you can
write about logging in.
•Examples:
•As a registered user, I am required to
log in so that I can access the system.
•As a forgetful user, I can request a
password reminder so that I can log in
if I forget mine.
“As a <user role>,
I <want/need/can/
etc> <goal>
so that <reason>.”
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Story-writing workshops
Includes whole team plus possibly some
external stakeholders
Typically not done every sprint
Brainstorm to generate stories
Goal is to write as many stories as possible
Some will be “implementation ready”
Others will be epics
No prioritization at this point
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Start with epics and iterate
As a frequent
flyer, I want to
book a trip using
miles.
As a frequent
flyer, I want to
rebook a trip I
take often.
As a frequent
flyer, I want to
request an
upgrade.
As a frequent
flyer, I want to
see if my
upgrade cleared.
As a frequent
flyer, I want to
see check my
account.
As a frequent
flyer, I want to
book a trip.
As a frequent
flyer, I want
to…
Frequent Flyer
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Agenda
What stories are
Why user stories
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So why user stories?
If requirements are
written down
The user will get
what she wants
then
At best she’ll get
what was written“You built what I
asked for, but it’s
not what I need.”
Shift focus from writing to talking
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Words are imprecise
Entrée comes
with
soup or salad
and bread. • (Soup or Salad) and Bread
• (Soup) or (Salad and Bread)
Which is right?
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Examples
The user can enter a
name. It can be 127
characters.
The system should
prominently display a warning
message whenever the user
enters invalid data.
• Must the user enter a
name?
• Can it be other than
127 chars?
• What does should
mean?
• What does prominently
display mean?
• Is invalid data deﬁned
elsewhere?
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Additional reasons
Stories are understandable
Developers and customers understand them
People are better able to remember events if
they are organized into stories†
Support and encourage iterative
development
Can easily start with epics and disaggregate
closer to development time
†Bower, Black, and Turner. 1979.
Scripts in Memory for Text.
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Yet more reasons
Stories are the right size for planning
Stories support opportunistic development
We design solutions by moving
opportunistically between top-down and
bottom-up approaches†
Stories support participatory design
†Guindon. 1990. Designing the Design Process.
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What if we had stories instead?
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Most importantly…
The story text we write on
cards is less important
than the conversations we
have.
Don’t forget the purpose
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mike@mountaingoatsoftware.com
www.mountaingoatsoftware.com
twitter: mikewcohn
(720) 890-6110
Mike Cohn
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Introduction to User Stories

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