The recent economic crisis, known as the 'great recession', has led to a closer examination of its causes and effects. The study found that in the majority of economic downturns in the US, declines in housing investment were the primary factor. Housing investment often decreased before other sectors, and its decline was larger than any other sector. This pattern has been consistent over the past 81 years, with housing playing a significant role in triggering recessions. Additionally, in the few recessions where housing was not involved, declines in national defense expenditures or non-residential fixed investment were the main drivers.