Monetary policy

 is the process by which the monetary authority of a country controls the supply of money, often targeting an inflation rate or interest rate to ensure price stability and general trust in the currency.

Quotes

 * Monetary policy decisions tend to regress toward the mean and to be inertial—and hence biased in just the same way that adaptive expectations are biased relative to rational expectations. But errors like that, while systematic, will generally be small and will tend to shrink over time. And, in return, the system builds in natural safeguards against truly horrendous mistakes.
 * Alan S. Blinder, Central Banking in Theory and Practice. 1998, p. 31