Implications of Aggregation with Common Factors
指出宏观变量由微观变量加总得到，其生成过程主要由微观机制中的共同因子决定，因此宏观关系比微观关系更简单，但微观实证可能遗漏决定宏观关系的共同因子成分。
Many observed macrovariables are simple aggregates over a large number of microunits. It is pointed out that the generating process of the macrovariables is largely determined by the common factors in the generating mechanisms of the microvariables, even though these factors may be very unimportant at the microlevel. It follows that macrorelationships are simpler than the complete microrelationships, but that empirical investigations of microrelationships may not catch those components, containing common factors, which will determine the macrorelationship. It is also shown that an aggregate expectation or forecast is simply the common factor component of the individual agents expectations.