Demand‐Driven Technical Change and Productivity Growth: Theory and Evidence from the Energy Policy Act
利用美国能源政策变化对玉米需求的外生冲击，采用双重差分法发现需求增长促使农民采用更优质种子，进而使生产率提高7%。
We present novel evidence on the effect of market size on technology adoption and productivity. Our tests exploit a natural experiment in the U.S. corn industry where changes to national energy policy created exogenous increases in demand. Difference‐in‐difference estimates show that the demand shock caused technical change as corn producers adopted higher quality seeds which in turn raised productivity by 7%. We develop a simple model that formalizes the mechanisms underlying our results.