On the Equilibrium Yen-Dollar Rate
提出长期均衡汇率的定义，强调供给因素的作用，并据此估算1973-87年日元对美元长期均衡汇率，发现供给因素是汇率长期变动的重要决定因素。
This paper presents a definition of the long-run equilibrium exchange rate that emphasizes the role of supply factors in addition to the more traditional price differential variables. Using this definition, we estimate the long-run equilibrium yen-dollar rate during the period of 1973-87. This calculation demonstrates that supply factors are in fact very important determinants of the long-run movement of the exchange rate. Despite the central role the exchange rates play in the economy, economists seem to doubt their own ability to explain, let alone predict, exchange rate movements. The reason is that in many cases structural exchange rate equations do not significantly outperform various other models that do not appeal to economic theory such as the random walk. (See, for example, Richard Meese and Kenneth Rogoff, 1983.) While we also share this pessimism concerning our ability to forecast exchange rates in the short run (intradaily to monthly or quarterly), we argue that it is possible to reasonably explain, if not predict, long-run movements. The long-run equilibrium rate is most often thought to be determined by purchasing power parity (PPP), which tends to focus only on price differentials. Medium-run divergences of the exchange rate from the long-run equilibrium are therefore commonly identified with fluctuations in the inflation-adjusted real exchange rate. This paper demonstrates, however, that the simple PPP is unsatisfactory because it emphasizes only the inflation differential. In the more elaborated theory of purchasing power parity, of course, the potential importance of supply-side real factors as critical determinants of the exchange rate has been well recognized. (See, for example, John M. Keynes, 1923; Rudiger Dornbusch, Stanley Fischer, and Paul A. Samuelson, 1977; Alan Stockman, 1980.) Nevertheless, in empirical applications and policy discussions these supply-side real factors have been curiously ignored: To our knowledge, an exception is David Hsieh (1982). The main point of this paper is to show that these supply-side factors actually have been very important determinants of the yen-dollar rate over the period of 1973 to 1987.