Ingrid Harvold Kvangraven — 200 Years of Ricardian Trade Theory: How Is This Still A Thing?

On Saturday, April 19th 1817, David Ricardo published The Principles of Political Economy and Taxation, where he laid out the theory of comparative advantage, which since has become the foundation of neoclassical, ‘mainstream’ international trade theory. 200 years – and lots of theoretical and empirical criticism later – it’s appropriate to ask, how is this still a thing?

This week we saw lots of praise of Ricardo, by the likes of The Economist, CNN, Forbes and Vox. Mainstream economists today tend to see the rejections of free trade implicit in Trump and Brexit as populist nonsense by people who don’t understand the complicated theory of comparative advantage (“Ricardo’s Difficult Idea”, as Paul Krugman once called it in his explanation of why non-economists seem to not understand comparative advantage). However, there are fundamental problems with the assumptions embedded in Ricardo’s theory and there’s little evidence, if any, to back up the Ricardian claim that free trade leads to benefits for all. On this bicentenary, I therefore think it’s timely to revisit some of the fundamental assumptions behind Ricardo’s theory of comparative advantage, that should have led us to consider alternative trade theories a long time ago....

Good summary backgrounder. "It's more complicated than that," the "that" being what is assumed.

The following quote contains an important lesson about logic and epistemology.

Rather than accept that there is something wrong with the exchange rate theory itself, empirical discrepancies are explained by measurement problems and/or imperfections in the market because of currency ‘manipulation’ (see for example Eichengreen 2013 or Gagnon 2012). In fact, neoclassical trade theory is so highly regarded that economists, almost across the board, cannot imagine any reason for China’s trade surplus with the US other than the Chinese manipulating their exchange rate in order to stimulate their exports.

What has happened here is that the theoretical model become the criterion for assessing truth rather than a model to be compared with observation in measurement.

Take probability theory. Probability theory shows the outcome of a long run roll of a coin toss, regardless of whether it is an ensemble of 1000 coins tossed at once or a single coin tossed a 1000 times. If the outcome does not converge on 0.50, then the fairness of the coin becomes suspect and not the theory.

This is not necessarily the case with a scientific theory. In the case of an anomaly scientists check the experiment but after checking and finding no errors, the theory becomes suspect. Repeated failures result in re-thinking the theory.

Because it is difficult to impossible to run controlled experiments in economics in many cases, trade being one of them, the dominant theory is never questioned. It serves as a criterion of truth whose truth is privileged from question.

Developing Economics

200 Years of Ricardian Trade Theory: How Is This Still A Thing?
Ingrid Harvold Kvangraven | PhD student in Economics at the New School for Social Research