Tariff
In contrast, in economic theory tariffs are viewed as a primary element in international trade with the function of the tariff being to influence the flow of trade by lowering or raising the price of targeted goods to create what amounts to an artificial competitive advantage. When tariffs are viewed and used in this fashion, they are addressing the country's and the competitors' respective economic healths in terms of maximizing or minimizing revenue flow rather than in terms of the ability to generate and maintain a competitive advantage which is the source of the revenue. As a result, the impact of the tariffs on the economic health of the country are at best minimal but often are counter-productive.
Tariff-rate quota
In a TRQ, the quota component works together with a specified tariff level to provide the desired degree of import protection. Essentially, a TRQ is a two-tiered tariff. The first Q imports entering within the quota portion of a TRQ are usually subject to a lower tariff rate called the Inside tariff quota rate or ITQR. Imports above the quota's quantitative threshold (Q) face a much higher (usually prohibitive) Outside tariff quota rate or OTQR. The Q units are called the quota volume, and this volume serves as the cut off between the ITQR and the OTQR.