Low productivity of agriculture as compared with productivity of other sectors of the economy is often alleged to be an undesirable condition in underdeveloped countries, because it signifies a misallocation of resources; if productivity of labour is lower in agriculture than in manufacturing and if the difference is not just due to amounts of co-operating factors, then the national income could be increased and people made more prosperous by transferring labour from farms where its productivity is low to factories where its productivity is higher. This simple idea is at the root of the suggestion that a country could benefit from a tariff on manufactures if that tariff induced labour to move out of agriculture and into manufacturing.2 Discussion of the issue has concentrated on the major premise of the argument, namely, that if productivity is low, then such and such a policy would be beneficial.3 The present article is a critique of the minor premise. It is proposed to examine the usual measure of productivity of agriculture to see whether the statistics really bear the implications attributed to them in the policy discussion. Productivity in each sector is usually measured as the ratio of the share of national income generated by that sector to the size of the labour force employed.4 In this article attention is called to four ways in which the usual statistics claimed to represent productivity may fail to do so.
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