Home > Ask the Software Quality Experts > Software Requirements Questions & Answers > Use cases don't need to include all system functionality details
Ask The Software Quality Expert: Questions & Answers
EMAIL THIS

Use cases don't need to include all system functionality details

Karl E. Wiegers EXPERT RESPONSE FROM: Karl E. Wiegers

Pose a Question
Other Software Quality Categories
Meet all Software Quality Experts
Become an Expert for this site


Software quality news and advice
Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us    Add to Google


>
QUESTION POSED ON: 13 February 2007
One analyst on my project team thinks we should put every bit of system functionality into a use case. Is that a good idea?

>
EXPERT RESPONSE
Not in most cases. I've seen many organizations get in trouble when they relied solely on use cases as being "The Requirements." Many analysts have told me that they handed their use cases to their developers, who got the general idea about the system, but the use cases were missing a lot of necessary functionality details the developers had to track down.

I regard use cases primarily as a tool for structuring conversations with users to understand the goals (or tasks) users are trying to achieve with the help of the software system. Use cases also help users envision how they might interact with the system to achieve those goals. From this information, the analyst can derive the necessary functionality that developers must implement to let the users achieve those goals or perform those tasks.

Even a well-written use case does not contain all the functionality developers need to know about, such as how to handle unsatisfied use case preconditions or how to enforce pertinent business rules. Often the analyst already knows about some functionality the system must contain, such as the need to provide login access or other security mechanisms. I see no value in packaging such requirements into a use case.

The ultimate deliverable from requirements development is a software requirement specification that contains the detailed functional requirements, nonfunctional requirements, and other supporting information. Use cases are a valuable way for the analyst to discover functional requirements. But I've never met anyone who found that use cases provided enough details about system functionality for developers to build the software.


Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us    Add to Google


RELATED CONTENT
Software Requirements
How to choose the right requirements tool
Why you should test requirements definitions
How to estimate change requests in requirements
Use cases: Who writes them, what data do you include?
How use cases facilitate the SDLC
Requirements engineering in an uncooperative environment
Scrum and requirements gathering
Requirements reporting beyond use cases
Requirements gathering with storyboards
How to elicit performance requirements

Use cases and misuse cases
Use cases: Who writes them, what data do you include?
How use cases facilitate the SDLC
Requirements reporting beyond use cases
Test cases from requirements specifications and use cases
Approaches to defining requirements within Agile teams
Getting started with Web application misuse cases
Developing use cases that support business goals
Requirements gathering, SRS and use cases
How to effectively elicit user interface requirements
How to communicate with the client for effective requirements engineering

RELATED GLOSSARY TERMS
Terms from Whatis.com − the technology online dictionary
use case  (SearchSoftwareQuality.com)

RELATED RESOURCES
2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems
Search Bitpipe.com for the latest white papers and business webcasts
Whatis.com, the online computer dictionary



Search and Browse the Expert Answer Center
Search and browse more than 25,000 question and answer pairs from more than 250 TechTarget industry experts.
Browse our Expert Advice

About Us  |  Contact Us  |  For Advertisers  |  For Business Partners  |  Site Index  |  RSS
SEARCH 
TechTarget provides enterprise IT professionals with the information they need to perform their jobs - from developing strategy, to making cost-effective IT purchase decisions and managing their organizations' IT projects - with its network of technology-specific Web sites, events and magazines.

TechTarget Corporate Web Site  |  Media Kits  |  Reprints  |  Site Map




All Rights Reserved, Copyright 2006 - 2008, TechTarget | Read our Privacy Policy 		  TechTarget - The IT Media ROI Experts