Experimental economicsExperimental economics is the application of experimental methods to study economic questions. Data collected in experiments are used to estimate effect size, test the validity of economic theories, and illuminate market mechanisms. Economic experiments usually use cash to motivate subjects, in order to mimic real-world incentives. Experiments are used to help understand how and why markets and other exchange systems function as they do. Experimental economics have also expanded to understand institutions and the law (experimental law and economics).
Medium of exchangeIn economics, a medium of exchange is any item that is widely acceptable in exchange for goods and services. In modern economies, the most commonly used medium of exchange is currency. The origin of "mediums of exchange" in human societies is assumed to have arisen in antiquity as awareness grew of the limitations of barter. The form of the "medium of exchange" follows that of a token, which has been further refined as money. A "medium of exchange" is considered one of the functions of money.
ScarcityIn economics, scarcity "refers to the basic fact of life that there exists only a finite amount of human and nonhuman resources which the best technical knowledge is capable of using to produce only limited maximum amounts of each economic good." If the conditions of scarcity didn't exist and an "infinite amount of every good could be produced or human wants fully satisfied ... there would be no economic goods, i.e. goods that are relatively scarce..." Scarcity is the limited availability of a commodity, which may be in demand in the market or by the commons.
Purchasing power parityPurchasing power parity (PPP) is a measure of the price of specific goods in different countries and is used to compare the absolute purchasing power of the countries' currencies. PPP is effectively the ratio of the price of a basket of goods at one location divided by the price of the basket of goods at a different location. The PPP inflation and exchange rate may differ from the market exchange rate because of tariffs, and other transaction costs.