Durin the project, requirements chan e for a variety of reasons. As needs chan e and as work proceeds, additional requirements are derived and chan es may have to be made to the existin requirements. It is essential to mana e these additions and chan es efficiently andeffectively. To effectively analyze the impact of the chan es, it is necessary that the source of each requirement is known and the rationale for any chan e is documented. The project mana er may, however, want to track appropriate measures of requirements volatility to jud e whether new or revised （75）are necessary.
