monetary unit assumption

An accounting guideline where the U.S. dollar is assumed to be constant (no change in purchasing power) over time. This allows an accountant to add one dollar from a transaction in 1946 to one dollar in 2009 and to show the result as two dollars. It also means that items that cannot be expressed in dollars do not appear in the financial statements. For example, how would you express on a company's balance sheet the value of loyal customers or a brilliant, aggressive management team?