When building an economic model, economists describe consumers using a utility function – that is, a function which takes as its input the bundle of goods that are being consumed and outputs a value called the utility, which can be roughly thought of as the subjective benefit the consumer experiences as a result of consuming that bundle of goods. A common utility function used in trade and other macroeconomic models is the CES (constant elasticity of substitution) function. A key feature of this function is that it implies that given fixed prices for all goods, the demand of a consumer is some fixed proportion of their income. That is, if their income doubles, they buy double the amount of every good. While this is mathematically useful for building a model of aggregate demand (the sum of demand of all consumers) and can produce accurate macroeconomic models, it sits badly with microeconomic empirical evidence. Engel’s law – which is more accurately an observation rather than a ...
A collection of often belated reactions to developments in UK politics. Written by Steven Rose and kindly edited by Ele Saltmarsh and Ewan Hill Norris.