Income elasticity of demand within individual consumer groups and the level of income elasticity of the entire market demand

Abstract

The paper is focused on the derivation of the mathematical relationship among the income-elasticity level of the entire market demand and the income-elasticity values of the demand functions of the consumers’ groups buying on the defined market. The determination of the mathematical term was based on the linearity of the relevant demand functions. Under the linearity assumption, the income elasticity coefficient of the entire market demand equals the weighted sum of the income-demand elasticities of the differentiated consumer groups buying on the given market. The weights in the aggregation formula are defined as the related demand shares, i.e. as the proportions of the groups’ demands to the entire market demand. The derived aggregation equation is quite held if no demand interactions (e.g. the snob or fashion effect) are recorded among differentiated consumers’ groups. The derived formula was examined by using empirical data about the consumer behaviour of Czech households in the market of meat and meat products (Czech Statistical Office). However, the application potential of the achieved term for the income-elasticity aggregations is much broader within the consumer-behaviour analysis. In addition to the subject aggregations of the demand functions, we can also apply the derived formula for the analysis and estimations of the income elasticities within the demand-object aggregations, i.e. the multistage analysis of the income elasticity of consumer demand. Another possibility of the use of the aggregation equation is for the evaluations and estimations of the income elasticity of the region-demand functions in relation to the subregions’ demands or reversely.