Comparing interest-rate spreads and money growth as predictors of output growth: Granger causality in the sense Granger intended

Output can be most accurately predicted on an in-sample basis through measuring the difference between the rate for six-month commercial paper and three-month treasury bills, through a calculation using regressions on the lines of Granger. Commercial paper is less accurate at predicting growth in future output using out-of-sample performance, and is only valid for the 1970s. However, the growth of the M2 measure of money performs better in forecasting future growth in output, performing better than the M1 measure of money, and the difference between the rate for federal funds and for treasury bonds.