The Business Impact Analysis (BIA) is the most important, and often the most overlooked, component of a comprehensive Business Continuity Management Program. 

A proper BIA will identify the most critical functions within the organization, so you can put the right resources and funding into protecting your most critical assets.  It can also uncover dependencies between functions, so you can make sure that a critical function has all dependent components recovered within the same time scale.

Dolgin Consulting recommends a BIA that includes both personal interviews and a questionnaire for data, answered by your most knowledgeable staff.