Alistair.Cockburn.us | Why I still use use cases - 1 views
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XP pretty much banned use cases, replacing them with the similar sounding “user stories”
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Scrum did similar, using the “product backlog” instead of user stories
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Yet as I go around projects, I keep running across organizations suffering from three particular, real, painful, and expensive problems
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User stories and backlog items don’t give the designers a context to work from
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don’t give the project team any sense of “completeness
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don’t provide a good-enough mechanism for looking ahead at the difficulty of upcoming work
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Staring at the set of extension conditions in a use case lets the analysts suss out which ones will be easy and which will be difficult, and to stage their research accordingly
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Here 5 reasons why I still write use cases
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The list of goal names provides executives with the shortest summary of what the system will contribute to the business and the users
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The main success scenario of each use case provides everyone involved with an agreement as to what the system will basically do, also, sometimes more importantly, what it will not do.
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The extension conditions of each use case provide the requirements analysts a framework for investigating all the little, niggling things that somehow take up 80% of the development time and budget
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The use case extension scenario fragments provide answers to the many detailed, often tricky business questions
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The full use case set shows that the investigators have throught through every user’s needs, every goal they have with respect to the system, and every business variant involved
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how much should be written up front to get the project estimate into a safe place
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several sticky parts for people using use cases
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iteration/sprint lengths are so short that it is not practical to implement an entire use case in just one of them.
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Writing good use cases (or any other requirements) requires thinking, communicating, and thinking again. It is much easier just to write user-story tags on index cards and let the project blow up later
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We have adopted many of the concepts of Agile development—such as daily build and test, build the smallest piece of functionality that delivers value, etc.—but have retained our up-front work. It’s worked extremely well
