预期、有偏性预期及其形成机制：宏观经济学的进展与争议

Expectation,Biased Expectation,and Its Mechanism:Macroeconomics' Progress and Debates

预期在宏观经济学及其发展中具有根本性的作用,但在预期是否有偏的问题上仍然存在着争议,预期的形成机制更是国际经济学界的难题。历史回顾发现,预期设定的变化与宏观经济学的发展紧密关联。从经验证据看,对多种数据、多种变量、多种主体等的研究发现,预期通常是有偏的,通常假设的无偏性预期或理性预期难以成立。而难点在于预期形成机制,目前主要从信息处理能力和适应性学习的角度刻画预期形成过程。在不同预期模型和信息处理能力设定下,宏观经济的波动解释和最优政策设计都有所不同,一旦引入有偏性预期,宏观经济学及宏观政策都将做相应的调整。整体上看,有偏性预期及其形成机制的研究仍然是个重大的挑战和前沿研究领域。

Expectation is fundamental in macroeconomics, but it remains a debate whether expectation is biased or not. Through the history review, we find the setting of expectation has a close link with the macroeconomics development. Generally, the empirical tests on multiple dataset, variables, agents, show the expectation is biased, and rational expectation hypothesis is hard to accept. The most difficult task is how to formulate the expectation formation. Under different settings, the explanation of fluctuation and the optimal policy would be different. We believe that if biased expectation is introduced, the macroeconomics and policy should be altered. Generally, the biased expectation and its formation mechanism remains a challenge, and it is also a frontier research field.