History of Macroeconomics Classical economists applied microeconomic models, or market clearing models, to economy-wide problems The failure of simple classical models to explain the prolonged existence of higl unemployment during the Great Depression provided the impetus for the development of macroeconomIcsHistory of Macroeconomics Classical economists applied microeconomic models, or “market clearing” models, to economy-wide problems. The failure of simple classical models to explain the prolonged existence of high unemployment during the Great Depression provided the impetus for the development of macroeconomics