▁external ities . ▁ ▁In ▁the ▁case ▁of ▁a ▁government ▁tax , ▁the ▁amount ▁of ▁the ▁tax ▁drives ▁a ▁w edge ▁between ▁what ▁consum ers ▁pay ▁and ▁what ▁produ cers ▁receive , ▁and ▁the ▁area ▁of ▁this ▁w edge ▁shape ▁is ▁equivalent ▁to ▁the ▁dead weight ▁loss ▁caused ▁by ▁the ▁tax . ▁ ▁The ▁area ▁represented ▁by ▁the ▁triangle ▁results ▁from ▁the ▁fact ▁that ▁the ▁intersection ▁of ▁the ▁supply ▁and ▁the ▁demand ▁curves ▁are ▁cut ▁short . ▁The ▁consumer ▁sur plus ▁and ▁the ▁producer ▁sur plus ▁are ▁also ▁cut ▁short . ▁The ▁loss ▁of ▁such ▁sur plus ▁that ▁is ▁never ▁rec oup ed ▁and ▁represents ▁the ▁dead weight ▁loss . ▁ ▁Some ▁econom ists ▁like ▁James ▁Tob in ▁have ▁argued ▁that ▁these ▁tri angles ▁do ▁not ▁have ▁a ▁huge ▁impact ▁on ▁the ▁economy , ▁but ▁others ▁like ▁Martin ▁Feld stein ▁maintain ▁that ▁they ▁can ▁seriously ▁affect ▁long - term ▁economic ▁tr ends ▁by ▁pivot ing ▁the ▁tr end ▁down wards ▁and ▁causing ▁a ▁magn ification ▁of ▁losses ▁in ▁the ▁long ▁run . ▁ ▁H icks ▁vs . ▁Marshall ▁It ▁is ▁important ▁to ▁make ▁a ▁distinction ▁between ▁the ▁H icks ian ▁ ▁( per ▁John ▁H icks ) ▁and ▁the ▁Marsh al li an ▁( per ▁Alfred ▁Marshall ) ▁demand ▁function ▁as ▁it ▁rel ates ▁to ▁dead weight ▁loss . ▁After ▁the ▁consumer ▁sur plus ▁is ▁considered , ▁it ▁can ▁be ▁shown ▁that ▁the ▁Marsh al li an ▁dead weight ▁loss ▁is ▁zero ▁if ▁demand ▁is ▁perfectly ▁el astic ▁or ▁supply ▁is ▁perfectly ▁in