, ▁domin ate ▁the ▁effect ▁of ▁changes ▁in ▁firm ▁prof its ▁in ▁social ▁w elf are ▁calculations . ▁ ▁G ern ot ▁Kle pper , ▁in ▁an ▁analysis ▁similar ▁to ▁K rug man ▁and ▁Bald win , ▁has ▁also ▁used ▁the ▁Br ander ▁Sp encer ▁and ▁other ▁models ▁to ▁analyze ▁the ▁effects ▁of ▁entry ▁into ▁the ▁transport ▁aircraft ▁industry . ▁He ▁included ▁the ▁effects ▁of ▁learning ▁during ▁the ▁production ▁process ▁which ▁depends ▁on ▁the ▁scale ▁of ▁production . ▁His ▁cal ibr ated ▁model ▁suggested ▁that ▁per ▁unit ▁production ▁costs ▁can ▁fall ▁by ▁as ▁much ▁as ▁ 2 0 % ▁if ▁total ▁production ▁is ▁double d . ▁In ▁that ▁case , ▁the ▁entry ▁of ▁another ▁firm ▁( in ▁this ▁case , ▁Air bus ) ▁into ▁the ▁market ▁would ▁decrease ▁per ▁firm ▁output ▁and ▁reduce ▁the ▁learning ▁and ▁scale ▁effects . ▁In ▁his ▁analysis , ▁the ▁entry ▁of ▁Air bus ▁would ▁cause ▁an ▁increase ▁in ▁consumer ▁sur plus , ▁but ▁this ▁would ▁be ▁smaller ▁than ▁the ▁resulting ▁loss ▁in ▁producer ▁sur plus . ▁ ▁Crit ic ism ▁ ▁In ▁general , ▁like ▁with ▁many ▁of ▁the ▁New ▁Trade ▁Theory ▁models , ▁the ▁results ▁of ▁the ▁Br ander ▁Sp encer ▁model ▁and ▁the ▁policy ▁pres cri ptions ▁it ▁generates ▁are ▁very ▁sensitive ▁to ▁the ▁underlying ▁assumptions ▁on ▁the ▁nature ▁of ▁the ▁industry ▁in ▁question , ▁the ▁information ▁available ▁to ▁the ▁national ▁government , ▁its ▁ability ▁to ▁cred ibly ▁commit ▁to ▁an ▁action ▁and ▁the ▁likely ▁response ▁of ▁foreign ▁govern ments . ▁Some ▁of ▁these ▁critic isms