Quality and trade with many countries and industries.

This paper investigates a trade model with horizontal and vertical product differentiations, many goods and many countries. It studies the impact of productivity, population changes and trade costs on the quality composition of exports. The analysis embeds within the same tractable model a series of empirical results, including Linder hypothesis and high-income countries' specialization in high quality good production. It also shows that high-quality goods exhibiting a high degree of differentiation are traded only by high-income countries. [ABSTRACT FROM AUTHOR]