Indexation is a technique to adjust income payments by means of a price index, in order to maintain the purchasing power of the public after inflation, while deindexation is the unwinding of indexation. Overview From a macroeconomics standpoint there are four main categories of indexation: wage indexation, financial instruments rate indexation, tax rate indexation, and exchange rate indexation. The first three are indexed to inflation. The last one is typically indexed to a foreign currency, mainly the US dollar. Any of these different types of indexation can be reversed (deindexation). Applying a cost-of-living escalation COLA clause to a stream of periodic payments protects the real value of those payments and effectively transfers the risk of inflation from the payee to the payor, who must pay more each year to reflect the increases in prices. Thus, inflation indexation is often applied to pension payments, rents and other situations which are not subject to regular re-pricing in the market. COLA is not CPI, which is an aggregate indicator. Using CPI as a COLA salary adjustment for taxable income fails to recognize that increases are generally taxed at the highest marginal tax rate whereas an individual's rising costs are paid with after-tax dollars - dollars commensurate with an individual's average after-tax level. Indexing tax brackets does not address this fundamental issue but it does effectively eliminate "bracket-creep". Indexation has been very important in high-inflation environments, and was known as monetary correction "" in Brazil from 1964 to 1994. Some countries have cut back significantly in the use of indexation and cost-of-living escalation clauses, first by applying only partial protection for price increases and eventually eliminating such protection altogether when inflation is brought down to single digits. Protecting one of the parties from the risk of inflation means that the price risk must be shifted to another party. For example, if state pensions are adjusted for inflation, the price risk is passed from the pensioners to the taxpayers. Wages When a government decides to index wages of government employees to inflation it is to transfer the risk of inflation away from government workers onto the government. Such a policy is to attempt to reduce inflationary expectation and in turn inflation when it is rising rapidly. Research by economists is ambivalent on the success of such policies. Some have deemed it a success including Friedman (1974), Gray (1976), and Fischer (1977). Others have considered it