Good Requirements Properties

Question 1

What are the big ten rules of writing good requirements?

Answer 1

~ Completeness
~ Atomicity
~ Consistency
~ Unambiguousness, clearness
~ Feasibility
~ Obligatoriness and up-to-date
~ Traceability
   * Vertical Traceability
   * Horisontal Traceability 
~ Modifiability
~ Ranked for:
   * Importance
   * Stability
   * Priority
~ Correctness and verifiability

Question 2

How can we be sure if a requirement is atomic?

Answer 2

A requirement is atomic if it cannot be broken down into separate requirements without loss or completeness, and it describes one and only one situation.

Question 3

How can we be sure if a requirement is complete?

Answer 3

The requirement is complete if it provides all the necessary information, if nothing is missed or left out for reasons such as “this is already clear to everyone”.

Question 4

How can we be sure if a requirement is consistent?

Answer 4

A consistent requirement should not contain internal contradictions and/or contradictions with other requirements and documents.

Question 5

How can we be sure if a requirement is unambiguous (clear)?

Answer 5

A requirement is unabmiguous (clear) if it is described without the use of jargon, non-obvious abbreviations and vague wording, and allows only one objective understanding.

Question 6

How can we be sure if a requirement is obligatory and up-to-date?

Answer 6

Any requirement should be obligatory and up-to-date, otherwise, if the requirement is not mandatory for implementation or is outdated, it should be removed.

Question 7

How can we be sure if a requirement is feasible?

Answer 7

A feasible requirement is the one that is technologically achieveable and may be implemented within the project budget and schedule.

Question 8

How can we be sure if a requirement is traceable?

Answer 8

Vertical traceability shows the connection between levels of requirements, horizontal traceability shows the connection between a requirement and a test plan paragraph, test cases, architectural solutions, etc.
Requirements management tools and/or traceability matrix are often used to ensure traceability.

Question 9

How can we be sure if a requirement is modifiable?

Answer 9

Modifiability characterizes the ease of making changes to individual requirements or to a set of requirements. With good modifiability changes go well without unexpected side effects.

Question 10

How and with what can any requirement be ranked in order to achieve the desired value?

Answer 10

Each requirement can and should be ranked by importance, stability and priority.
~ Importance shows how the success of the project depends on the success of the implementation of the requirement.
~ Stability shows the likelihood that in the foreseeable future the requirement will not be changed.
~ Priority shows what requirements should be implemented earlier or later.

Question 11

How can we be sure if a requirement is correct and verifiable?

Answer 11

Correctness and verifiablility state that it is possible to create an objective test case(s) that clearly shows that the requirement is implemented correctly and the behavior of the application exactly corresponds to the requirement.