Relative Prices and Relative Prosperity
各国实际投资率与收入水平的正相关主要由投资品相对产出的价格差异驱动，穷国投资率低并非因投资税或关税高，而是生产投资品及消费品以换取投资品的效率低下。
The positive correlation between real investment rates and real income levels across countries is driven largely by differences in the price of investment relative to output. The high relative price of investment in poor countries is due to the low price of consumption goods in those countries. Investment prices are no higher in poor countries. Thus, the low real investment rates in poor countries are not driven by high tax or tariff rates on investment. Poor countries, instead, appear to be plagued by low efficiency in producing investment goods and in producing consumer goods to trade for them.