As a BA I want to provide requirements that are concise as possible. If requirements are not concise enough this can lead to costly changes to a solution. I intend to demonstrate this by comparing user stories with requirements and highlighting why user stories provide higher quality results. By doing so I hope to persuade you why user stories deliver better solutions.
Here I define
User story: As a <actor>,
I want <goal/desire> so that <benefit>
Requirement: The system shall provide <goal/desire>
Where items in “<>” are variables. The user story
conveys more information than the requirement. That is the actor and the benefit. They are concisely defined in one statement.
With requirements the actor can be determined by the mapping
between requirement and use case but additional information (the reference) is
required which increases the chance of error.
The justification column in the requirements catalogue is
often not written as concisely as the requirement as it’s separation from the goal/desire can leads to being treated as "for information purposes only". Furthermore when two actors are involved
the justification can be muddled or biased.
This is why I believe the user story creates better quality because it is so concise in all respects.This conciseness can lead to developing a more complex but a
much more valuable solution. Say we have
a user story and a requirement with the same goal/desire. Two “errors” are
possible in the requirement:
- The requirement is mistakenly applied to two
- The justification reduces the fidelity of what the different
benefits each actor may hope to achieve
If either case occurs then a single solution may result for both actors where extra benefit could derived in having different solution for each.
As the cost of fixing software based on a requirement misunderstanding increases markedly as it
is developed, tested and deployed the cost of separating the single solution
into two later will be much more expensive.
The user story has been associated with Agile development,
but it’s adoption has become more universal and I hope I have convinced you to
use them as well (if you don’t already).