In economics, deflation is a decrease in the general price level of goods and services. Deflation occurs when the inflation rate falls below 0% (a negative inflation rate). This should not be confused with disinflation, a slow-down in the inflation rate (i.e., when inflation declines to lower levels). Inflation reduces the real value of money over time; conversely, deflation increases the real value of money –- the currency of a national or regional economy. This allows one to buy more goods with the same amount of money over time. Economists generally believe that deflation is a problem in a modern economy because it increases the real value of debt, and may aggravate recessions and lead to a deflationary spiral. Deflation occurred periodically in the U.S. during the 19th century (the most important exception was during the Civil War). This deflation was at times caused by technological progress that created significant economic growth, but at other times it was triggered by financial crises — notably the Panic of 1837 which caused deflation through 1844, and the Panic of 1873 which triggered the Long Depression that lasted until 1879. These deflationary periods preceded the establishment of the U.S. Federal Reserve System and its active management of monetary matters. Episodes of deflation have been rare and brief since the Federal Reserve was created (a notable exception being the Great Depression) while U.S. economic progress has been unprecedented. Although the values of capital assets are often casually said to “deflate” when they decline, this should not be confused with deflation as a defined term; a more accurate description for a decrease in the value of a capital asset is economic depreciation (which should not be confused with the accounting convention of depreciation, which are standards to determine a decrease in values of capital assets when market values are not readily available or practical).