This report on quantification of Essentiality (W) and Utilization (U) terms extends the scope of the basic expression for system effectiveness (Es = ADC) to include the additional "W" and "U" paramenters needed for the quantification of multi-functioned and multi-missioned systems. Methods and procedures for applying these terms to system effectiveness quantification are discussed and simple examples to demonstrate the principles of usage are included. The need to look at the system being quantified in terms of its level in the mission/function hierarchical tree is explained. The relationships between system elements (hardware, software, and personnel) and performance functions are discussed and illustrated with examples. Two methods for applying the "W"'and "U" weight factors, LOGIC AND (weak link model) and LOGIC OR (degraded operational modes model) are described and examples are shown for these cases.