MR. BERNANKE: Well, after those interventions and trying to stabilize the financial system, we then had to turn to monetary policy. And with the zero lower bound being effective we did quantitative easing, we did forward guidance, we did a variety of other new tools, or at least new for the United States.
What’s your retrospective? I mean, there was a conference on Friday where there was a paper which argued quantitative easing wasn’t particularly effective. And what’s your thinking on the whole suite of tools at this point.
MS. YELLEN: I thought it was an all-hands-on-deck-type of situation, and we should do everything that we could plausibly think of to try to help. And it’s a time when, I think 2009 and ’10, when short-term interest rates were effectively at 0; long-term rates were still over 3 percent. It seemed clear to me, and I think to you, as well, that there was plenty of scope to bring long-term rates down.
So the two major obvious things that we did were communications to try to shape market thinking about what the likely path of short-term interest rates would be, that would then have bearing on longer-term interest rates and asset purchases.
So I think my read, there are a lot of papers, people will study it for a long time. I know the paper that was presented at the U.S. Monetary Policy Forum cast doubt on the effectiveness of asset purchases. But I think my reading of the literature on this, I think the overwhelming set of studies to my mind, document that large-scale asset purchases were effective in lowering the term premium and longer-term rates and bringing it down. Exactly how much, you know, I’m not sure and it’s hard to tell. There’s very limited evidence.
And the event studies that people typically do, they capture some of what happens, but I think some of what we did was anticipated. Maybe people didn’t know the exact quantities that we would do or how long a program might last, but it was expected that the Fed would do something more. So I think it’s event studies have problems in capturing what happened.
I think that the forward guidance that we gave was also quite effective in lowering expectations about the path of short-term interest rates. Many people I think, including people in the FOMC, when we lowered rates to zero thought this would be a situation that would last for a short time, not a year or two, not terribly long. You know, it was seven years that we held rates at zero and people didn’t expect that.
And there’s a big debate about whether forward guidance can be effective if it’s so-called Delphic rather than Odyssian. Namely it’s just conveying the committee’s expectations as opposed to a specific commitment, and a lot of the guidance we gave was Delphic. But nevertheless, I think it did influence market expectations that rates would stay low for long.
And the general policy of when you’re against the zero bound, holding rates at zero for a longer time than would otherwise be called for I think is a generally sound approach to policy. People came to understand.

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