Affirmative and Definite Business Rules
When you write Business Rules, use clear, concise, affirmative statements such as "Negative amounts are highlighted on application screens using a contrasting color."
This is the type of statement that is most easily validated and, at a later stage, verified. (To validate a statement is to say whether or not it correctly describes the desired target situation. To verify the statement is to determine whether or not the current version of the system actually supports it, or behaves in the way described by the statement.)
Avoid words and phrases that make statements less definite, or that express a wish or a plan rather than a fact. For example, avoid modal verbs such as "must", "will", "should", "could", and "may". Do not write "Negative amounts could be highlighted on application screens using a contrasting color."
Adjectives that make a statement less definite, such as "possible", "probable" or "desirable" should also be avoided.
Do not use "must" or "necessary" or similar words to indicate how important it is to implement a rule. This is expressed in USoft TeamWork by setting the Priority attribute of the rule.
There is a difference between writing down a Business Rule and actually implementing that Rule so that the evolving information system supports it. A Business Rule should simply state what is the case IF it is implemented. It should not attempt to indicate whether or not it is already implemented; this is expressed in USoft TeamWork by entering Implementations for the Rule.