Editing Use case (section)

== Misconceptions ==
{{Expand section|date=July 2015}}

Common misunderstandings about use cases are:

'''User stories are agile; use cases are not.'''

Agile and [[Scrum (development)|Scrum]] are neutral on requirement techniques. As the Scrum Primer<ref>{{cite web |author1=Pete Deemer |author2=Gabrielle Benefield |author3=Craig Larman |author4=Bas Vodde |title=The Scrum Primer: A Lightweight Guide to the Theory and Practice of Scrum (Version 2.0) |url=http://www.infoq.com/minibooks/Scrum_Primer |publisher=InfoQ |date=17 December 2012}}</ref> states,

<blockquote>'' Product Backlog items are articulated in any way that is clear and sustainable. Contrary to popular misunderstanding, the Product Backlog does not contain "user stories"; it simply contains items. Those items can be expressed as user stories, use cases, or any other requirements approach that the group finds useful. But whatever the approach, most items should focus on delivering value to customers.''</blockquote> Use case techniques have evolved to take Agile approaches into account by using use case slices to incrementally enrich a use case.<ref name=":0" />

'''Use cases are mainly diagrams.'''

[[Craig Larman]] stresses that "use cases are not diagrams, they are text".<ref>{{cite book|last=Larman|first=Craig|title=Applying UML and patterns|year=2005|publisher=Prentice Hall|isbn=0-13-148906-2|pages=63–64}}</ref>

'''Use cases have too much UI-related content.'''

As some put it,{{who|date=March 2022}}

<blockquote>'' Use cases will often contain a level of detail (i.e. naming of labels and buttons) which make it not well suited for capturing the requirements for a new system from scratch.''</blockquote>

Novice misunderstandings. Each step of a well-written use case should present ''actor'' goals or intentions (the essence of functional requirements), and normally it should not contain any user interface details, e.g. naming of labels and buttons, UI operations, etc., which is a ''bad'' practice and will unnecessarily complicate the use case writing and limit its implementation.

As for capturing requirements for a new system from scratch, ''use case diagrams'' plus ''use case briefs'' are often used as handy and valuable tools, at least as lightweight as user stories. {{Citation needed|date=March 2022}}

'''Writing use cases for large systems is tedious and a waste of time.'''

As some put it,{{who|date=March 2022}}

<blockquote>'' The format of the use case makes it difficult to describe a large system (e.g. CRM system) in less than several hundred pages. It is time-consuming and you will find yourself spending time doing an unnecessary amount of rework.''</blockquote>{{Citation needed|date=March 2022}}

Spending much time writing tedious use cases which add no or little value and result in a lot of rework is a ''bad smell'' indicating that the writers are not well skilled and have little knowledge of how to write quality use cases both efficiently and effectively. Use cases should be authored in an iterative, incremental, and evolutionary (''agile'') way. Applying use case templates does not mean that all the fields of a use case template should be used and filled out comprehensively from up-front or during a special dedicated stage, i.e. the requirement phase in the traditional ''waterfall'' development model.

In fact, the use case formats formulated by [[#Templates|those popular template styles]], e.g. the RUP's and the Cockburn's (also adopted by [[Oracle Unified Method|the OUM method]]), etc., have been proved in practice as valuable and helpful tools for capturing, analyzing and documenting complex requirements of large systems. The quality of a good use case documentation (''model'') should not be judged largely or only by its size. It is possible as well that a quality and comprehensive use case model of a large system may finally evolve into hundreds of pages mainly because of the inherent complexity of the ''problem'' in hand, not because of the poor writing skills of its authors. {{Citation needed|date=March 2022}}