Chapter 10 short-term economic fluctuations econ 2010 macroeconomics. Steep slide in economy as unsold goods pile up . Fed plans to inject another trillion to aid economy . World bank says global economy will shrink in 09 . U. s. economy has passed through its worst recession in 25 years. Business cycles are short-term fluctuations in gdp and other variables. A depression is a particularly severe recession. A peak is the beginning of a recession: high point of the business cycle. A trough is the end of a recession: low point of the business cycle. An expansion is a period in which the economy is growing at a rate significantly above normal. A boom is a strong and long lasting expansion. Nber declared a recession december 2007: previous recession ended november 2001, 73 month expansion. Four important monthly indicators used to date recessions: industrial production, total sales in manufacturing, wholesale, and retail, non-farm employment, real after-tax household income.