منافع حاصل از تجارت و اندازه گیری بهره وری کل عوامل

We develop and calibrate a model where differences in factor endowments lead countries to trade different goods, so that the existence of international trade changes the sectorial composition of output from one country to another. Gains from trade reflect in total factor productivity. We perform a development decomposition, to assess the impact of trade — and barriers to trade — on measured TFP. In our sample, the median size of that effect is about 6.5% of output, with a mean of 17% and a maximum of 89%. Also, the model predicts that changes in the terms of trade cause a change of productivity, and that effect has an average elasticity of 0.73.

A large literature (e.g., Mankiw et al., 1992; Prescott, 1998; Klenow and Rodriguez-Clare, 1997; Caselli, 2005 among many) has studied the cross-country differences in total factor productivity, that is, those differences in output per-capita that cannot be explained by corresponding differences in available inputs. In these exercises, it is assumed that the technology that transforms inputs into output is the same across countries, except for a single TFP coefficient that changes the effectiveness of the overall production process, but does not change the way different inputs interact with each other. The functional forms used in these analyses are chosen assuming that countries do not trade with each other, and are calibrated using parameters that give a good fit to the data of developed nations. In this paper, we quantify the impact of international trade on Total Factor Productivity (TFP). Trade leads to a more efficient allocation of resources across sectors, and thus may affect aggregate productivity even if sectorial productivities are not allowed to differ across countries. Since barriers to trade do vary significantly, the degree to which gains from trade are exploited may be a relevant component in explaining cross-country TFP differences.

In this paper we presented evidence that gains from trade are relevant to measured productivity. We used a very simple version of the Hecksher–Ohlin model so that the only reason countries trade are factor differences, and tariffs, by changing the relative domestic prices of tradeable goods, lead to inefficient sectorial allocations. This contrasts with Eaton and Kortum (2002) Ricardian trade model in which there is a continuum of goods and countries have differential access to technology. In that model efficiency varies across commodities and countries. As opposed to Rodriguez-Clare (2007), which builds on Eaton and Kortum (2002), there is no diffusion in our model. Nonetheless, the model is able to capture some important features of the international commerce — poor countries do trade because of factor differences — and so our measured gains from trade may be seen as a (large) lower bound of the gains from openness. As a matter of fact, they are close to those Rodriguez-Clare (2007) obtained in the pure trade model.