consumption behavior; increasing the money supply is like "pushing on a string". Economist Paul Krugman described the U.S. 2009 recession and Japan's lost decade as liquidity traps. One remedy to a liquidity trap is expanding the money supply via quantitative easing or other techniques in which money is effectively printed to purchase assets, thereby creating inflationary expectations that cause savers to begin spending again. Government stimulus spending and mercantilist policies to stimulate exports and reduce imports are other techniques to stimulate demand. He estimated in March 2010 that developed countries representing 70% of the world's GDP were caught in a liquidity trap. Paradoxes of thrift and deleveraging Behavior that may be optimal for an individual (e.g., saving more during adverse economic conditions) can be detrimental if too many individuals pursue the same behavior, as ultimately, one person's consumption is another person's income. Too many consumers attempting to save (or pay down debt) simultaneously is called the paradox of thrift and can cause or deepen a recession. Economist Hyman Minsky also described a "paradox of deleveraging" as financial institutions that have too much leverage (debt relative to equity) cannot all de-leverage simultaneously without significant declines in the value of their assets. In April 2009, U.S. Federal Reserve Vice Chair Janet Yellen discussed these paradoxes: "Once this massive credit crunch hit, it didn't take long before we were in a recession. The recession, in turn, deepened the credit crunch as demand and employment fell, and credit losses of financial institutions surged. Indeed, we have been in the grips of precisely this adverse feedback loop for more than a year. A process of balance sheet deleveraging has spread to nearly every corner of the economy. Consumers are pulling back on purchases, especially durable goods, to build their savings. Businesses are cancelling planned investments and laying off workers to preserve cash. And financial institutions are shrinking assets to bolster capital and improve their chances of weathering the current storm. Once again, Minsky understood this dynamic. He spoke of the paradox of deleveraging, in which precautions that may be smart for individuals and firms—and indeed essential to return the economy to a normal state—nevertheless magnify the distress of the economy as a whole." Predictors A handful of measures exist that are held to generally predict the possibility of a recession: The U.S. Conference Board's Present Situation Index year-over-year change turns negative by more than 15