"Question: On the one extreme, we have models by people like Mark Zandi at Moody's who say that the fiscal multiplier for the spending initiatives we're discussing are on the order of 1.5. On the other hand, we have people like Robert Barro at Harvard who say there's zero or negative. How would you go about applying the Lucas critique to these types of models to sort of educate us in how we should think about the validity of these models?
LUCAS: Do I need the Lucas critique for -- I'm with Barro is the short answer. (Laughter.) The Moody's model that Christina Romer -- here's what I think happened. It's her first day on the job and somebody says, you've got to come up with a solution to this -- in defense of this fiscal stimulus, which no one told her what it was going to be, and have it by Monday morning.
So she scrambled and came up with these multipliers and now they're kind of -- I don't know. So I don't think anyone really believes. These models have never been discussed or debated in a way that that say -- Ellen McGrattan was talking about the way economists use models this morning. These are kind of schlock economics.
Maybe there is some multiplier out there that we could measure well but that's not what that paper does. I think it's a very naked rationalization for policies that were already, you know, decided on for other reasons. I don't -- I'd like to talk about the Lucas critique but I don't -- I don't think we can -- (chuckles) -- deal with that issue. "
LOL, I wonder if Christy R. got the license plate of that bus as it ran over her. The whole transcript of Lucas' talk is here.