A quantification of the efficiency by which competing packaging materials deliver product to market. It is derived by comparing the volume of product delivered per pound of packaging. It is one way to quantify the achievement of source reduction, i.e., delivering the most product per unit of packaging. ("Factoring the Value of Source Reduction into Packaging Use/Post-Use Economics," Ronald Perkins, Recycle 93 Sixth Annual Forum, Davos, Switzerland).