Milton Friedman and the Emergence of the Permanent Income Hypothesis
研究了弗里德曼永久收入假说从1940年代到1960年代的演变，揭示其如何成为现代消费理论范式，并指出永久收入等不可观测概念的含义随工具变化而流动。
The purpose of this paper is to investigate the evolution of Milton Friedman's permanent income hypothesis from the 1940s to 1960s, and how it became the paradigm of modern consumption theory. Modelling unobservables, such as permanent income and permanent consumption, is a long-standing issue in economics and econometrics. While the conventional approach has been to set an empirical model to make "permanent income" measurable, the historical change in the meaning of that theoretical construct is also of methodological interest. This paper will show that the concepts of unobservables, especially permanent income, in Friedman's work was fluid and depended on the instruments used.