As a matter of theory, it is I think important to see the expression as an evolution from the quantity equation. One of the steps, emphasized by Hansen as early as 1927 in Business Cycle Theory, Its Development and Present Status, was Aftalion, see pp. 100-101 in my book Money Interest and Public Interest. "Aftalion summarized his theory in the equation R = PQ, where R is money income, P the price level, and Q real income. In this equation, the nominal value of real output (PQ) is related directly to money income (R) rather than to the quantity of money times the velocity of money (MV), as was customary in the tradition of the quantity theory of money." Subsequently, I would also emphasize the importance of the development of national income accounts, which treat your equation as a definition. Keynes (1940 "How to Pay for the War" was an early use of the new national income accounting framework. Perry ----- Original Message ----- From: "Stephen Marglin" <[log in to unmask]> To: "SHOE" <[log in to unmask]> Sent: Tuesday, September 8, 2015 9:57:46 AM Subject: Re: [SHOE] Fwd: origins of Y=C+I+G+(X-M) Samuelson deals with the closed economy version Y = C + I (that is, without G and X-M) in “Stability of Equilibrium,” Econometrica, 1941, pp 113ff. “Fiscal Policy and Income Determination,” QJE , 1942, has the formula Y = C + E, where E is the sum of private investment and government expenditure, in a footnote on p 584. Steve Marglin From: Societies for the History of Economics [mailto:[log in to unmask]] On Behalf Of Steve Kates Sent: Monday, September 07, 2015 8:10 PM To: [log in to unmask] Subject: [SHOE] Fwd: origins of Y=C+I+G+(X-M) I was wondering whether anyone could help me here. The farthest back I can trace the use of the basic macro expression Y=C+I+G+(X-M) - now usually rendered Y=C+I+G+NX - is to Samuelson's 1948 text. In the General Theory there is D=D1+D2 (p: 28), which is later turned into Y=C+I in the work of others before 1948. But so far as that full equation goes, I am wondering whether it has an earlier pre-Samuelson provenance. I would be most grateful for any assistance. -- Dr Steven Kates Associate Professor School of Economics, Finance and Marketing RMIT University Building 80 Level 11 / 445 Swanston Street Melbourne Vic 3000 Phone: (03) 9925 5878 Mobile: 042 7297 529 -- Dr Steven Kates Associate Professor School of Economics, Finance and Marketing RMIT University Building 80 Level 11 / 445 Swanston Street Melbourne Vic 3000 Phone: (03) 9925 5878 Mobile: 042 7297 529 -- Dr Steven Kates Associate Professor School of Economics, Finance and Marketing RMIT University Building 80 Level 11 / 445 Swanston Street Melbourne Vic 3000 Phone: (03) 9925 5878 Mobile: 042 7297 529