1. A computer implemented system analysis and design method for use in a complex business environment by a set of linked business processes, comprising steps of: providing an (eXtensible Markup Language) XML-based BDML (Business Decision Markup Language) framework representing a world view of each of a plurality of business decisions associated with business processes from among the set of linked business processes, the BDML world view including a business objective tag definition for quantitatively representing a business objective, constraints tag definition, assumptions tag definition, data tag definition, and an underlying model tag definition for identifying a business decision mathematical algorithm; capturing in the BDML framework a world view of a plurality of business decisions that occur in the set of linked business processes, wherein the capturing includes specifying and documenting each of the plurality of business decisions as a BDML portable document structured according to said XML-based BDML framework, having a business objectives tag quantitatively representing the decision's business objective, constraints tag representing the decision's constraints, assumptions tag representing the decision's assumptions, data tag representing data related to the decision, and an underlying model tag identifying the business decision mathematical algorithm applied in the decision; checking for logical consistency between different business decision based on the decision's respective BDML portable documents and their respective said tags.