How Much Did the Liberty Shipbuilders Learn? New Evidence for an Old Case Study
利用新发现的档案资料，质疑了二战自由轮建造中“干中学”解释的若干关键假设，发现生产率增长主要源于资本深化、质量下降及技术变化，而非单纯的学习效应。
This paper uses previously unavailable historical records to show that several assumptions central to a learning by doing explanation of productivity growth in the construction of Liberty ships during World War II are mistaken. Impressive increases in output per worker recorded at one of the largest shipyards in the program, Calship, are shown to be strongly associated with increases in capital intensity and with a reduction in quality, where the latter is measured by the probability of a ship developing serious fractures that threatened the lives of its crew. Capital deepening and quality change, in conjunction with changes in production technologies and capacity utilization, account for virtually all the increase in labor productivity.