The Determinants of Price Elasticity. Основные факторы ценовой эластичности спроса

Consider two extreme cases. Suppose first that the price of all cigarettes is raised 1 per cent, perhaps because the cigarette tax has been raised. Do you expect the quantity of cigarettes demanded to fall by 5 per cent or by 0,5 per cent? Probably the latter. People who can easily quit smoking have already done so. A few smokers may try to cut down but this effect is unlikely to be large. In contrast, suppose the price of one particular brand of cigarettes is increased by 1 per cent, all other brand prices remaining unchanged. We should now expect a much larger quantity response from buyers. With so many other brands available at unchanged prices, consumers will switch away from the more expensive brand to other brands that basically fulfil the same function of nicotine provision. For a particular cigarette brand the demand elasticity could be quite high.

Ease of substitution implies a high demand elasticity for a particular good. In fact this example suggests a general rule. The more narrowly we define a commodity (a particular brand of cigarette rather than cigarettes in general or oil rather than energy as a whole), the larger will be the price elasticity of demand.