Most trade barriers work on the same principle: the imposition of some sort of cost on trade that raises the price of the traded products. If two or more nations repeatedly use trade barriers against each other, then a trade war results.
Economists generally agree that trade barriers are detrimental and decrease overall economic efficiency, this can be explained by the theory of comparative advantage. In theory, free trade involves the removal of all such barriers, except perhaps those considered necessary for health or national security. In practice, however, even those countries promoting free trade heavily subsidize certain industries, such as agriculture and steel.
The scarcity of information on trade barriers is a major problem to the competitiveness of developing countries. In the past, many companies relied on spreadsheets and manual processes to keep track of compliance issues related to incoming and outgoing shipments, which risks potential errors and losses of business opportunity. As a result, in 2015 the International Trade Centre launched NTM Business Surveys, a database listing non-tariff barriers from company perspectives to help users identify regulatory and procedural obstacles to trade in 23 developing countries.