Prices: sources, problems, solutions

Price currents and newspapers are major sources of information on prices during the eighteenth and nineteenth centuries, but drawing conclusions about trends and fluctuations in values from the quotations in these sources poses several recurrent difficulties. After discussing the origins of the prices in these sources, we use a range of examples, mainly involving commodity prices, to illustrate important problems in working with historical price data. These include missing observations and price inertia, varying gaps between low and high price quotations, and the splicing together of price series from different sources or for different commodity qualities. The last two problems often arise from changes over time in the detail with which prices for heterogeneous commodities were reported.