much higher price; By relocating the site of production to another nation where production costs are lower, because of lower input costs (wage costs and materials/equipment supply costs). That way, they pocketed an extra profit. By campaigning for protective tariffs shielding local industry from foreign competition. That, Marxian economists argue, is essentially why the international dynamic of capital accumulation and market expansion takes the form of imperialism, i.e., an aggressive international competition process aimed at lowering costs, and increasing sales and profits. As Marx put it, Empirical indicators The terms of trade. This refers to the relative prices of goods and services traded on international markets, specifically the weighted average of a nation's exports relative to its import prices, as indicated by the ratio of the export price index to the import price index, measured relative to a base year. Accounting analysis of product unit values, i.e., the composition of the various costs included in the final market price of a commodity (the price to the final consumer who uses or consumes the product). If for example it is found that an increasing fraction of that sale price represents costs other than direct production and transport costs, but instead profit, interest and rent income, then unequal exchange in trade has probably increased. But because of the "creative" gross and net income & expenditure accounting that is done, this is often not easy, since various incomes and expenditures are included under headings which make it difficult to understand what the costs were actually for, or what activity gave rise to the incomes. The change in the shares of net income between social classes and groups. If the discrepancy between the gross and net incomes of one social class, relative to another social class, increases, then a transfer of claims to wealth is occurring. This could be due to less income generated in production, or to income transferred in exchange (trading), or to taxation. We can compare also the actual average labour hours put in by one social class, to the net income accruing to that social class. The trend in the cost structure of production of a country as a whole, or particular sectors, which refers to the amount of capital expenditures not directly related to the actual production of a product, i.e. financial costs incurred in addition to materials, equipment and labour (interest payments, incidental expenses, insurance, taxes, rents and