Information Technology Reference
In-Depth Information
• Too much design: one of the greatest problems in requirement analysis is
finding the solution to the defined problem in the same stage. A metarequire-
ment is a design decision that is presented in the form of a system (product)
requirement. Metarequirements describe situations and items that are not
externally-discernible characteristics of the system to be delivered. True met-
arequirements are not suggestions. They are items that the customer absolutely
requires in the solution.
• Failure to identify properties: Sometimes, software engineers make the mis-
take of assuming that any solution to the customer's problem can only contain
items that were explicitly mentioned in the problem description and/or the
problem-space module. Some of the requirements properties could be implicit
and hidden in other requirements.
• Irrelevant information: One straightforward way to describe a solution to a
problem is to focus on what is essential, while ignoring what is inessential.
7.9 Chapter Summary and Conclusions
A requirement is a quality that a software system must have. This could be an
activity that it must perform, an interface that it must contain, or an environment
within which it must operate. Requirements are criteria that a system must meet if
it is to work as intended, and thus if a software engineering project is to be
successfully completed. In the last chapter, we discussed the process of eliciting
these requirements from the client and from the end user. Those requirements first
elicited, however, are far from perfect.
In this chapter we discussed the analysis phase of the software life cycle. This
phase is focused on refining, improving, and finalizing the requirements specifi-
cation, and a formalized understanding of the system that will be the primary
resource for the rest of the development process. At the beginning of the analysis
phase, requirements usually suffer from one or more of the following problems:
• omitted information
• contradictory information
• ambiguous information
• inaccurate information
• irrelevant information
The analysis phase seeks to correct these problems through the systematic
evaluation, modification, and refinement of a system's requirements gathered
during the requirements elicitation phase, into a final, functional requirements
specification. During analysis, systems analysts review requirements with a goal of
identifying and correcting missing or erroneous information. Interviews used in the
requirements elicitation phase are reviewed. When the analysts discover errors or
omissions during this evaluation period, new information is gathered to fill in the
