Can Field Experiments Return Agricultural Economics to the Glory Days

摘要

This session collects three very interesting papers offering different perspectives on the recent commodity price spike. Sumner’s paper puts recent developments in a 150-year perspective. The top panel of my figure 1 is similar to his series for corn. The figure highlights the very dramatic downward trend in the real price of corn, which Sumner notes convincingly refutes the thesis of Malthus. But, in part the recent moves look modest because the trend had previously brought the price so low. A 0.1 change in the logarithm corresponds to a 10% change in the price, so that when plotted on a logarithmic scale as in the bottom panel, price moves of a given vertical distance are equal in percentage terms. The recent move is in fact bigger in percentage terms than the spike of World War I and comparable to the 1970s commodity price boom.