. ▁lit res ▁of ▁water ▁per ▁$ 1 ▁spent ▁on ▁product . ▁In ▁national ▁economic ▁and ▁sust ain ability ▁account ing ▁it ▁can ▁be ▁calculated ▁as ▁units ▁of ▁resource ▁exp ended ▁per ▁unit ▁of ▁G DP . ▁When ▁applied ▁to ▁a ▁single ▁person ▁it ▁is ▁expressed ▁as ▁the ▁resource ▁use ▁of ▁that ▁person ▁per ▁unit ▁of ▁consumption . ▁Rel atively ▁high ▁resource ▁intens ities ▁indicate ▁a ▁high ▁price ▁or ▁environmental ▁cost ▁of ▁converting ▁resource ▁into ▁G DP ; ▁low ▁resource ▁intensity ▁indicates ▁a ▁lower ▁price ▁or ▁environmental ▁cost ▁of ▁converting ▁resource ▁into ▁G DP . ▁ ▁Resource ▁product ivity ▁and ▁resource ▁intensity ▁are ▁ ▁key ▁concepts ▁used ▁in ▁sust ain ability ▁measurement ▁as ▁they ▁measure ▁attempts ▁to ▁dec ou ple ▁the ▁connection ▁between ▁resource ▁use ▁and ▁environmental ▁de grad ation . ▁Their ▁strength ▁is ▁that ▁they ▁can ▁be ▁used ▁as ▁a ▁metric ▁for ▁both ▁economic ▁and ▁environmental ▁cost . ▁Although ▁these ▁concepts ▁are ▁two ▁sides ▁of ▁the ▁same ▁coin , ▁in ▁practice ▁they ▁involve ▁very ▁different ▁approaches ▁and ▁can ▁be ▁viewed ▁as ▁reflect ing , ▁on ▁the ▁one ▁hand , ▁the ▁efficiency ▁of ▁resource ▁production ▁as ▁outcome ▁per ▁unit ▁of ▁resource ▁use ▁( resource ▁product ivity ) ▁and , ▁on ▁the ▁other ▁hand , ▁the ▁efficiency ▁of ▁resource ▁consumption ▁as ▁resource ▁use ▁per ▁unit ▁outcome ▁( resource ▁intensity ). ▁The ▁sust ain ability ▁objective ▁is ▁to ▁maxim ize ▁resource ▁product ivity ▁while ▁minim izing ▁resource ▁intensity . ▁ ▁See ▁also ▁ ▁Bio e conom ics ▁E con oph ys ics ▁Energy ▁and ▁Environment