Grantham said he believes the major input to lower rates has been a sustained US Fed policy, since just before 1995, of pushing down short-term rates.

The claim has two parts: (a) from just before 1995 to 2016 the Fed kept up a policy of pushing short-term rates down (a long-term trend of lower policy rates and accommodation, including easing in 1998, 2001-03, 2008-15, and asymmetric responses such as the 'Greenspan put'); (b) this policy was the major cause of lower rates. True if the Fed rate history shows a sustained easing bias over the period and credible analysis supports Fed policy as the main driver of lower rates. Mostly true if (a) holds but evidence supports Fed policy as a major cause alongside others of similar weight. Mixed if (a) holds broadly, but with notable tightening phases (1994, 1999-2000, 2004-06) that weaken 'sustained', and the causal claim is contested. Mostly false if the rate record contradicts a sustained push-down, or if most research credits other factors (global savings glut, demographics, lower inflation, the falling natural rate) as the main causes, so the Fed is a contributing factor stated as the main one. False if the Fed did not systematically lower short-term rates over the period.

Set before the research began.

1. E1 Table Data - Federal Funds Effective Rate FRED, Federal Reserve Bank of St. Louis (data from Board of Governors of the Federal Reserve System, H.15)

   “| 2008-12-01 | 0.16 | | 2009-01-01 | 0.15 |”

2. E2 Monetary Policy in a Low R-star World - San Francisco Fed Federal Reserve Bank of San Francisco (Economic Letter, by John C. Williams) · 15 August 2016

   “The underlying determinants for these declines are related to the global supply and demand for funds, including shifting demographics, slower trend productivity and economic growth, emerging markets seeking large reserves of safe assets, and a more general global savings glut”

3. E3 Monetary Policy in a Low R-star World - San Francisco Fed Federal Reserve Bank of San Francisco (Economic Letter, by John C. Williams) · 15 August 2016

   “Importantly, this future low level of interest rates is not due to easy monetary policy; instead, it is the rate expected to prevail when the economy is at full strength and the stance of monetary policy is neutral.”

4. E4 The Global Saving Glut and the U.S. Current Account Deficit Board of Governors of the Federal Reserve System (speech by Ben S. Bernanke, hosted by FRASER, St. Louis Fed) · 10 March 2005

   “This shift by developing nations, together with the high saving propensities of Germany, Japan, and some other major industrial nations, has resulted in a global saving glut.”

The rate data (E1) shows only two near-zero months in 2008-09, so it cannot show whether the Fed pushed rates down steadily from just before 1995. Only one 2016 San Francisco Fed letter (E2, E3) addresses the causes of lower rates, and E4 does not discuss interest rates. That is not enough to show that most research credits factors other than Fed policy.