A monthly consumer price index traces changes in the monthly cost of a year’s consumption using a sample of prices. But in some months the prices that can be sampled will temporarily exclude some of the products that were bought in the base year, Christmas trees providing a textbook example. Worse still, it becomes permanently impossible to observe prices for sampled products that have been completely superseded. There are methods for dealing with these two problems, but they leave serious and irremediable defects in the index.

There is a high degree of symmetry between economic goods and economic bads. Snow, litter and street mud are cited as examples. Economic growth obviously results in an increase in the supply of bads as well as goods. In addition, however, because it raises the value of time it can turn goods into bads and it can result in an end to the transformation of bads into goods. This is illustrated in some detail by two case studies for nineteenth century London, relating to domestic refuse and to horse manure. As a result of economic growth, horse manure had almost ceased to be an economic good and had become an economic bad by the end of the century.

The treatment of owner-occupied dwellings in Consumer Price Indexes varies between countries and is the subject of continuing controversy. Ralph Turvey explains the alternative possible treatments and reasons for disagreement.