Productivity Growth without Technical Change in European Agriculture before 1850
研究发现，19世纪初美国和英国农业工人的人均产出远高于东欧和中世纪英格兰，但技术变革和人均土地丰裕度无法解释这一差异，主要原因是劳动强度更高。
Output per farm worker in the northern United States and Britain in the early nineteenth century was many times that inEastern Europe or in medieval England and wages were correspondingly higher. Technical progress explains little of the high American and British productivity in the early nineteenth century, nor, in the American case, does abundant land per worker. Instead, most of the difference derived from more intense labor in America and Britain.