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Requirements Management |
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What is Requirements Management? Why do we need it, what are its advantages and what are the likely pitfalls?
Contents
What is Requirements Management?
The need for Requirements Management
The purpose of Requirements Management
Information management of Requirements Management
Advantages of Requirements Management
Good Requirements
Bad Requirements
Differentiation of requirement document text types
What is Requirements Management?
Requirements Management can be defined as the skilful administration, guidance, control and use of an expression of a demand, an essential condition
or a need.
The central aim of Requirements Management is to ensure
that the delivered item or system meets the needs of the user. Requirements establish an understanding of the user's needs and provide a measure
against which success can be gauged. Requirements Management is the process of tracking 'what is required' througout the life of the item or
system, from initial development through to delivery.
The need for Requirements Management
The development of complex systems presents many challenges to system engineers. Even the development of a small system requires an understanding of
all the needs of the user, together with the ability to communicate cause and justification for any changes. Therefore a process of management and
control of this information is needed.
The purpose of Requirements Management
The foremost purpose of Requirements Management is the
ability to ensure that the delivered system satisfies
the needs of the users.
Information management of Requirements Management
Because systems often change and evolve throughout the life cycle, there can be difficulty in tracking such changes and evolution.
Requirements Management meets these needs by the consistent application of information capture, information storage, information analysis and
manipulation, and information dissemination.
The key to the solution of Management of Requirements
is the inclusion and application of organisation, traceability,
analysis and visualization of the information.
Advantages of Requirements Management
The aim of the Requirements Management process is the development of an item or system, which exactly meets the needs of the user, within a time
scale, and for a price that satisfies the user.
The advantage of the use of Requirements Management is
the reduction in problems that may occur if a process
is not followed. The following list of problems are some of those that
may, and often do,
occur when requirements are not managed:
- The needs of the user are not met.
- Unimportant work is done.
- Non-required functions are developed.
- Time is wasted.
- Money is wasted.
- Resources are misused.
- Money spent / invested that will not provide return.
- Increased likelihood of bugs or errors.
Problems such as these may lead to cost and time over-runs,
non-payment of money, a non-saleable product, or the
reduction of the possible profit.
Good Requirements
A good requirement can be defined as a complete and correct
statement of a need. When writing requirements or judging
the quality of a good requirement, the following list
of factors below should be considered:
- Atomic: a single need is stated.
- Testable: the need can be proven to have been met.
- Unambiguous: the requirement cannot be misunderstood.
- Concise: no unnecessary wording.
- Complete: the need is fully covered.
- Correct: the requirement is what is needed.
Bad Requirements
Requirements are bad if they are:
- Woolly / vague: open to argument.
- Overly complex: difficult to understand / prone to error.
- Confusing or unclear: open to misinterpretation.
- Unrequired / over specified: 'Gilding the lily', wouldn't it be
nice if...?
Differentiation of level of requirement
Some functions or attributes in a system may be more necessary than others. It is therefore important that the level of need of all requirements
is captured and understood by all parties.
The following terms and definitions are frequently used
to define these levels of need:
- Mandatory requirements: shall / will / must.
- Highly desirable: should.
Not mandatory but agreement of non-incorporation is likely to be required
- Wishes: would like.
Non essential
- Wouldn't it be nice if (WIBNI): similar to wishes, a 'nice thought'.
Non essential
In addition, it is not uncommon to have statements which,
although not requirements themselves, may impact the
understanding of specific requirements. These are generally
in one of two forms:
- Clarifications: intended to clear any misunderstanding or misinterpretation
of the requirement.
- Insights: provides an understanding into need for the requirement
or the intended use for the attribute or function.
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