Marginal Intra-Industry Trade, a concept originating in
international economics, refers to the degree to which the change in a country's exports over a certain period of time are essentially of the same products as its change in imports over the same period. The concept is therefore closely related to that of
intra-industry trade, that being the export and import of the same items, but concerns changes in exports and imports between two points in time as opposed to their values at a given point in time. The concept is thought to be useful for ascertaining the amount of adjustment costs associated with changing
trade flows or the degree to which changes in trade might be responsible for changes in the
distribution of income. Several formulas have been proposed to quantify this concept but the most widely used is that of Shelburne (1993).