This journal article describes a study of the global impact of the Great Recession of the late 2000s and early 2010s on trends for unsheltered homelessness in twenty of the largest municipalities in the Organisation for Economic Cooperation and Development (OECD). The authors hypothesized a direct relationship between the recession and the level of homelessness. The Great Recession resulted in changes in homeless populations throughout the world. This economic crisis impacted economies in ways that put severe pressures on housing, particularly at lower-income brackets. The recession was generated by a housing bubble, which then constricted capital markets for housing. After the immediate crisis, economic stabilization was followed by stagflation or deflation with flat or decreasing wages in middle- to low-income brackets and high unemployment. Many governments responded with austerity measures to decrease public spending. The researchers focused on the roofless population (i.e., those without shelter of any kind, sleeping rough). In addition to affecting adults and families, the recession also affected unaccompanied youth. One 2012 study found that 75 percent of high school principals in California reported that the number of houseless or living insecure had increased among their students, even in schools within affluent neighborhoods. Results indicate no clear correlation between levels of homelessness and the Great Recession in most cities. While some cities experienced large increases in their identified homeless populations (e.g., London, Vienna, Berlin, Stockholm, Auckland, and Madrid), homelessness declined in other locations following the recession (e.g., Sydney, Budapest, and Tokyo). The authors conclude that there is a relationship between housing crises/recessions and street homelessness that is, however, mediated by factors such as policies, culture, demographics, and migration.