Its research covers microeconomics, macroeconomics and Marxian economics. Economics has two components&colon; macroeconomics and microeconomics. This dichotomy is roughly analogous to the difference between microeconomics and macroeconomics. In the 1920s, John Maynard Keynes prompted a division between microeconomics and macroeconomics. AP Microeconomics is often taken in conjunction with or after AP Macroeconomics. He specializes in the fields of macroeconomics, monetary economics and time series econometrics. He has written extensively in the fields of macroeconomics, econometrics and public policy. Many German Post-Keynesians are organized in the Forum Macroeconomics and Macroeconomic Policies. New classical macroeconomics further challenged the Keynesian school. Two main assumptions define the New Keynesian approach to macroeconomics. In macroeconomics it is reflected in an early and lasting neoclassical synthesis with Keynesian macroeconomics. He is a prominent proponent of Modern Monetary Theory in macroeconomics. His research focuses on macroeconomics and finance. In 2011, he set up Greenmantle LLC, an advisory business specializing in macroeconomics and geopolitics. New classical macroeconomics and rational expectations hypothesis can explain how and why inflation targeting works.