1. A computer implemented method of managing human resources comprising: providing a business strategy; based on said business strategy, periodically developing a set of rules for specifying supply sources for human resource supplies and for assigning individual human resources to satisfy demands; based on said set of rules, periodically developing first-level plans specifying said supply sources; and based on a most-recent of said first-level plans and on said set of rules, periodically developing second-level plans for assigning at least one of said individual human resources to satisfy at least one selected demand, wherein said second level plans are developed more often said first-level plans and said first-level plans are developed more often than said set of rules.