Documentation Guidelines - Requirements Engineering and Management for Software Development Projects - page 237

A.3.7.4 Shall, Should, Will, Would, Must, May and Can

1. Shall—The word 'shall' will be used to indicate the advisory (not obligatory)
character of a requirement.
2. Should—The word 'should' will be used to indicate that the requirement is
advisory and not obligatory.
3. Will—The word 'will' will be used to indicate the obligatory (not advisory)
character of a requirement.
4. Would—The word 'would' will be used to indicate that the requirement is
obligatory (not advisory).
5. Must—The word 'must' will not be used to express obligatory character.
6. May—The word 'may' will be used when permissive character or probability
of occurrence is implied.
7. Can—The word 'can' will not be used to express either permissive character or
probability of an occurrence.

A.4 Recommended and Not Recommended Usage

It may be noted that the list given below is by no means complete. However, this is
a first list that may be improved further.

Not recommended Recommended

At the present time Now

Despite the fact that Although

For the reason that Since/because

On behalf of For

So as to To

Inter alia Among other things

Mutatis mutandis With necessary alterations

Ipso facto By the very fact

Erroneous Wrong

Annihilate Destroy

Recapitulate Recall

Facilitate Help

Utilize Use

Competence Skill

Above mentioned clauses Clauses mentioned above

Adequate enough Adequate or Enough

Afore mentioned Mentioned earlier

Brief details Details

Enclosed herewith Enclosed

Equipments Equipment

May invariably Shall invariably

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