8  For example, in an interesting recent paper, Bordo and Jeanne (2002) used mechanical rules to identify booms in stock and residential property prices since 1970 in 15 industrial countries.
They defined a “boom” to be a situation in which asset-price growth over a three-year period lies significantly above its long-run average and a “bust” to be a situation in which the threeyear asset-price growth is correspondingly lower than normal. Out of 24 boom episodes that they identified for stock prices, only 3 were followed by busts.