Measuring Marginal Intra-Industry Trade. — Trade liberalisation and adjustment: how important is intra-industry trade? This paper focuses on the appropriate measurement of intra-industry trade as indicator of structural adjustment costs. It is argued that existing dynamic versions of the Grubel-Lloyd index reflect horizontal trade only and classify vertical intra-industry trade with inter-industry trade. The paper proposes a method to distinguish between horizontal and vertical trade and applies these techniques to emerging trade between the EU and the economies of central and eastern Europe.