SIR,-Dr Phillips questions (April 17, p 1008) the value of twin studies in estimating the genetic component in the most common diseases of adult life. He points out that the intrauterine environment of twins, monozygous as well as dizygous, may be different and that this distinction may account for later differences in disease prevalence between co-twins. Thus, a greater concordance between mon...

I n most industrialized economies, periods of above average inflation tend to be associated with above average economic activity, for example, as measured by a relatively low unemployment rate. This statistical relationship, known as the Phillips curve, is sometimes invoked when economic commentators suggest that monetary policy should not try to suppress signs of inflation. But this interpreta...

In 1958, A.W. Phillips discovered a strong negative correlation between inflation and unemployment in United Kingdom data. Continuing controversy surrounds the long-run trade-off suggested by a curve he drew through these observations. We conduct a wide-ranging investigation of the post-war U.S. Phillips correlations and Phillips curve. Many economists view the Phillips correlations as chimeric...

A number of theoretical models predict that the slope of the Phillips curve increases with trade openness, but cross-country studies provide little evidence for such a correlation. We highlight two reasons for this …nding. Firstly, the strength of the relationship may depend on the extent of exchange rate adjustment, which is a potential determinant of output and in‡ation dynamics in open econo...