Empirical studies of firms within industries consistently report substantial heterogeneity in measures of performance such as size and productivity. This paper explores the consequences of joint heterogeneity on the supply side (sellers) and the demand side (buyers) in international trade using...

Two otherwise identical firms that enter the same market in different months, one in January and one in December, will report dramatically different annual sales for the first calendar year of operations. This partial year effect in annual data leads to downward biased observations of the level...