分享一篇文献New Trade Models, New Welfare Implication

New Trade Models, New Welfare Implications
By Marc J. Melitz and Stephen J. Redding
We show that endogenous rm selection provides a new welfare
margin for heterogeneous rm models of trade (relative to homoge-
neous rm models). Under some parameter restrictions, the trade
elasticity is constant and is a sucient statistic for welfare, along
with the domestic trade share. However, even small deviations
from these restrictions imply that trade elasticities are variable and
dier across markets and levels of trade costs. In this more general
setting, the domestic trade share and endogenous trade elasticity
are no longer sucient statistics for welfare. Additional empir-
ically observable moments of the micro structure also matter for
welfare.
JEL: F12, F15
Keywords: rm heterogeneity, welfare gains from trade, trade pol-
icy evaluation