When introducing the concept of supply and demand, economists often make qualitative statements about the behavior of consumers and producers. For example, the law of demand states that as the price of a good or service increases, the demand for that good or service decreases. The law of supply indicates that the quantity of goods tends to increase as the market price of the goods rises. Although these laws are useful, they do not cover everything that economists want to incorporate into the supply and demand model. As a result, economists have developed quantitative methods, such as resiliency, to provide more details about market behavior. In short, elasticity is the relative tendency of certain economic variables to change in response to other variables. In economics, it is important to understand how responsiveness such as demand and supply responds to prices, income, prices of related commodities, and so on. For example, when gasoline prices rise by one percent, will the demand for gasoline drop a little? Answering such questions is critical to economic and policy decisions, so economists have proposed a concept of resilience to measure the responsiveness of the economy.�����%�!