With the continuation of the great depression in the 1930’s explanations of economic activity began to be widely studied..

Keynesian

Explanation:

Keynesian economics is an economic theory which states that to boost growth government should increase the demand. According to this theory consumer demand is the main driving force in an economy.

Keynesian economists support expansionary fiscal policies and consider government spending as an important tool. Its major drawback is that overdoing this policy increases inflation. This theory was developed by John Maynard Keynes in the 1930's.

It was used by Franklin D. Roosevelt for New Deal program , he increased the government debt and created sixteen new agencies and laws. All these agencies created more than four million jobs.