The Great Recession was particularly severe and has endured far longer than most recessions. Economists now believe it was caused by a perfect storm of declining home prices, a financial system heavily invested in house-related assets and a shadow banking system highly vulnerable to bank runs or rollover risk. It has lasted longer than most recessions because economically damaged households were unwilling or unable to increase spending, thus perpetuating the recession by a mechanism known as the paradox of thrift. Economists believe the Great Recession wasn’t foreseen because the size and fragility of the shadow banking system had gone unnoticed.
The recession has had an inordinate impact on macroeconomics as a discipline, leading economists to reconsider two largely discarded theories: IS-LM and the paradox of thrift. It has also forced theorists to better understand and incorporate the financial sector into their models, the most promising of which focus on mismatch between the maturity periods of assets and liabilities held by banks.