As of September 2021, Mohamed El-Erian, Ken Rogoff and Larry Summers were talking about rising risks of stagflation.

True if by about 14 September 2021, Mohamed El-Erian, Ken Rogoff and Larry Summers had each publicly discussed rising stagflation risk (in articles, interviews or social media) in roughly the preceding months. Mostly true if all three had warned of inflation or overheating risks and at least two used the stagflation framing explicitly. Mixed if only two of the three discussed stagflation risks. Mostly false if only one did. False if none of them was discussing stagflation risk then, or if they publicly dismissed it.

Set before the research began.

1. E1 Larry Summers blasts $1.9 T stimulus as 'least responsible' economic policy in 40 years The Hill · 20 March 2021

   “Summers warned that there was a one-third chance that inflation would accelerate over the next several years, with the U.S. possibly facing stagflation, or economic stagnation.”

2. E2 Prophet The International Economy (TIE), interview with Larry Summers by David Smick

   “I was surprised by the complacency surrounding inflation early this year.”

3. E3 Prophet The International Economy (TIE), interview with Larry Summers by David Smick

   “I think the forces coming out of China look to be, right now, more deflationary than stagflationary.”

4. E4 Case for 'sticky' inflation strengthens, as energy crisis intensifies Investorideas.com Newswire · 27 October 2021

   “Rogoff's observation, made at the end of August, that supply shocks are happening both today and in the 1970s, is playing out perfectly with respect to the energy crisis that we see unfolding, particularly in China and Europe.”

5. E5 (none) The International Economy (TIE), interview by David Smick · 2021

   “The argument I made that has gotten more attention is the concern about overheating the economy, given that the size of the stimulus substantially exceeded any reasonable estimate of the size of the GDP gap by a substantial margin.”

6. E6 (none) The International Economy (TIE), interview by David Smick · 2021

   “I think the forces coming out of China look to be, right now, more deflationary than stagflationary.”

7. E7 Case for 'sticky' inflation strengthens, as energy crisis intensifies Investorideas.com (Richard Mills / Ahead of the Herd) · 27 October 2021

   “Rogoff's observation, made at the end of August, that supply shocks are happening both today and in the 1970s, is playing out perfectly with respect to the energy crisis that we see unfolding, particularly in China and Europe.”

8. E8 Case for 'sticky' inflation strengthens, as energy crisis intensifies Investorideas.com (Richard Mills / Ahead of the Herd) · 27 October 2021

   “Harvard economics professor Ken Rogoff, writing for Project Syndicate, suggests the parallels between the 2020s and the 1970s just keep growing.”

9. E9 Summers Watch - The American Prospect The American Prospect · 12 April 2022

   “As John Cassidy recently observed in The New Yorker, Summers in March 2021 forecast three possible scenarios—a one-third chance of stagflation; a one-third chance that “the Fed hits the brakes hard” and we get recession; and a one-third chance of growth that “will moderate in a non-inflationary way.””

10. E10 Mohamed A. El-Erian | Bloomberg Opinion: Fed Raises Risk of Policy Mistake and Market Accidents - Gramercy - Emerging Markets Investing Gramercy · 15 July 2021

    “On July 15, Mohamed A. El-Erian published a Bloomberg Opinion article discussing the impact of inflation and monetary policy mistakes.”

Summers explicitly named stagflation as a possible outcome in March 2021, giving it a one-third chance (E1, E9), and later spoke of overheating risk (E5). For Rogoff, the only evidence is a later secondhand account of his end-of-August observation about supply shocks and growing parallels with the 1970s; none of the quoted text uses the word stagflation (E4, E8). For El-Erian, the evidence shows only a July 2021 article on inflation and the risk of Fed policy mistakes, with no stagflation framing quoted (E10). Only one of the three is shown using the stagflation framing explicitly, and the evidence neither confirms nor rules out that the other two did, so it cannot settle which tier of the criteria applies.