Question: Which British economist was Erwin Rothbarth a research assistant for that changed the theory of economics?
Sentence (from "John Maynard Keynes"): John Maynard Keynes, 1st Baron Keynes {'1': ", '2': ", '3': ", '4': "} ( ; 5 June 1883 – 21 April 1946), was a British economist whose ideas fundamentally changed the theory and practice of macroeconomics and the economic policies of governments.
Relevant evidence: Yes