In mainstream economics, inflation is a rise in the general level of prices, as measured against some baseline of purchasing power. The prevailing view in mainstream economics is that inflation is caused by the interaction of the supply of money with output and interest rates. In general, mainstream economists divide into two camps: those who believe that monetary effects dominate all others in setting the rate of inflation, or broadly speaking, monetarists, and those who believe that the interaction of money, interest and output dominate over other effects, or broadly speaking Keynesians. Related terms include: deflation, a general falling level of prices, disinflation, the reduction of the rate of inflation, hyper-inflation, an out of control inflationary spiral, and reflation, which is an attempt to raise prices to counter act deflationary pressures.
Measures of inflation
Measuring inflation is a question of econometrics that is, finding objective ways of comparing nominal prices to real activity. In many places in economics, "real" variables need to be compared, in order to calculate GDP, effective interest rate and improvements in productivity. Each inflationary measure takes a "basket" of good and services, then the prices of the items in the basket are compared to a previous time, then adjustments are made for the changes in the goods in the basket itself. For example if a month ago canned corn was sold in 10 oz. jars, and this month it is sold in 9.5 oz jars, then the prices of the two cans have to be adjusted for the contents. The result is the amount of increase in price which is attributed to "inflation" and not to improvements in productivity. This means that there are many measures of inflation, depending on which basket of goods and services are used as the basis for comparison. Different kinds of inflation measure are used to determine the real change in prices, depending on what the context is. Examples of common measures of inflation include:
• Consumer price indexes (CPIs) which measure the price of a selection of goods purchased by a "typical consumer". • Producer price indexes (PPIs) which measure the price received by a producer. This differs from the CPI in that price subsidization, profits, and taxes may cause the amount received by the producer to differ from what the consumer paid. There is also typically a delay between an increase in the PPI and any resulting increase in the CPI. Producer price inflation measures the pressure being put on producers by the costs of their raw materials. This could be "passed on" as consumer inflation, or it could be absorbed by profits, or offset by increasing productivity. • wholesale price indexes, which measure the change in price of a selection of goods at wholesale, prior to retail mark ups and sales taxes. These are very similar to the Producer Price Indexes. • commodity price indexes, which measure the change in price of a selection of commodities. In the present commodity price indexes are weighted by the relative importance of the components to the "all in" cost of an employee. Inflation measures are often modified over time, either for the relative weight of goods in the basket, or in the way in which goods from the present are compared with goods from the past. This includes hedonic adjustments and "reweighing" as well as using chained measures of inflation. As with many economic numbers, inflation numbers are often seasonally adjusted in order to differentiate expected cyclical cost increases, versus changes in the economy. Inflation numbers are averaged or otherwise subjected to statistical techniques in order to remove statistical noise and volatility of individual prices. Finally, when looking at inflation, economic institutions sometimes only look at subsets or "special indexes". One common set is inflation ex-food and energy, which is often called "core inflation". In classical political economy, inflation referred...