Risk quantification is the process of evaluating the risks that have been identified and developing the data that will be needed for making decisions as to what should be done about them. Risk management is done from very early in the project until the very end.
For this reason qualitative analysis should be used at some points in the project, and quantitative techniques should be used at other times. The objective of quantification is to establish a way of arranging the risks in the order of importance. In most projects there will not be enough time or money to take action against every risk that is identified.