A country's suitability for entry into a currency union depends on a n
umber of economic conditions. These include, inter alia, the intensity
of trade with other potential members of the currency union, and the
extent to which domestic business cycles are correlated with those of
the other countries. But international trade patterns and internationa
l business cycle correlations are endogenous. This paper develops and
investigates the relationship between the two phenomena. Using thirty
years of data for twenty industrialised countries, we uncover a strong
and striking empirical finding: countries with closer trade links ten
d to have more rightly correlated business cycles.