I.Analytical Framework, Concepts, Definitions, and Classifications
• Definition: Foreign trade indices provide an overall measure of unit value and volume changes of exported and imported goods.Value index: The index measures changes of imports and exports value by base year value. Terms of trade index:Terms of trade is the ratio of export unit value index to import unit If the terms of trade index number increases, it is described as a favourable movement (a unit of exports will buy more imports).If the terms of trade index number decreases,it is described as a worsening or deterioration of the terms of trade (a unit of exports will buy fewer imports).Calculated indicesa) Unit value indexb) Volume indexc) Terms of trade indexd) Value index • Classification:a) SITC Rev.3 (The bulletin is issued by the classification)b) BECc) ISIC Rev.3d) ISIC Rev.4• International and regional guidelines: Foreign trade indices have been calculated by Eurostat and UN concepts and methods.
Valuation: Exports are valued free on board (f.o.b.) and imports on cost, insurance and freight (c.i.f.). • Period: Monthly, Quarterly, Yearly• Method: Fisher formula, geometric mean of Laspeyres and Paasche, is used for the foreign trade unit value indices with the base year 2010. The value indices are obtained as the ratio of current values to the arithmetic average of the base year values.The volume indices are produced as the ratio of the value indices to the fisher unit value indices.• Valuation: Unit value indices are calculated by US Dollars and Turkish Lira
Sources: Main data source is customs declarations. Data on electricity, natural gas and crude petroleum is received from firms.