Cross Price Elasticity of Demand

1472 Words6 Pages
Nasos Gkekas Paper 1 Economics HL IB 2013-2014 a)Cross-price elasticity of demand(XED) is a measure of the responsiveness of demand for one good to change in the price of another good and involves demand curve shifts. It provides us with information on whether demand curve increases or decreases, and on the size of demand curve shifts. The formula for XED is the following: XED=percentage change in quantity demanded of good Xpercentage change in price of good Y XED has positive, negative and zero sign and its sign depends on a series of important factors. As cross-price elasticity of demand has to deal with the demand of two goods, we have to understand what kinds of goods exist. In an economy there are substitute goods and complementary goods. Two goods are substitutes if they satisfy a similar need, whereas two goods are complements if they tend to be used together. By definitions we can see that substitute goods are competitive goods and complements are dependent on each other. According to the law of demand, which states that there is a negative causal relationship between the price of a good and its quantity demanded over a particular time period, ceteris paribus, what happens with substitutes is that when the price of one good increases, this will result in an increase in the demand for the other good and vice versa. This of course does determine which value XED takes when two goods are substitute ones. The value will be always positive ( XED>0) because the demand of one good and the price of other good change in the same direction and the nominator will be always greater than the dominator, according to the formula of XED. Let’s consider Pepsi and Coca-Cola. A fall in the price of Coca-Cola will result in a fall in the demand of Pepsi. How much the market of Pepsi will be affected will be shown on the following graph : From the graph we can see
Open Document