I was going to comment on this comment by Russ Roberts
He treats it like a discovery of fact. As in “Blinder and Zandi weren’t sure of the distance between the earth and the sun but when they measured it, they found it was about 93,000,000 miles.” That isn’t the way econometrics works.
We can and should talk about this more but I would suggests that exactly how econometrics works.
After all no one has – in my jargon – taken a ruler to the sun. No one has actually trekked from the earth to the sun with a tape measure to get its distance.
Indeed no one has even been to the sun or even out of earth’s orbit. People confidently mock those who say the sun is not at the center of the solar system but has anyone been outside the solar system to look down and check? Certainly not.
All of this is based on measurement and inference. And people trust the measurements and inferences of physical scientists even when they make wild conclusions based on highly technical derivations, complex models and slight differences in obscure measurements.
Two guys screw together a few half-silvered mirrors and all of a sudden the passage of time is just a fancy illusion. Is that more convoluted than Donohue and Levitt?
Anyway, Robin Hanson makes my longer point for me
They key difference, I think, is that more interested parties see themselves as losing if the public listens to economists, and these parties therefore dispute economists in public. Such interested parties also influence individual economists, and so weaken within-economics consensus. In contrast, few care enough about what physicists say to dispute them in public.

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Wednesday ~ September 14th, 2011 at 12:28 am
Alex Godofsky
The other difference is that it’s really REALLY easy to reproduce e.g. the half-silvered mirrors.
Wednesday ~ September 14th, 2011 at 12:57 am
DocOc
But of course with various data sources, economic models are also “easy” to reproduce.
I’d argue more people are capable of mining data for economics models these days than building competent physics experiments.
Wednesday ~ September 14th, 2011 at 12:59 am
gregransom
2 body astronomy has simple, linear mathematical laws, natural kinds, and physical constants.
Economics doesn’t have anything of the kind.
Falsely pretending that it does, doesn’t do anything to actually make economics have these characteristics.
It only falsely fools people into a bogus mistaken belief about the nature of the ordered phenomena at hand in economics.
Wednesday ~ September 14th, 2011 at 1:18 am
Jason Collins
Is there a single, credible argument that the distance to the sun is not 93,000,000 miles?
Wednesday ~ September 14th, 2011 at 2:27 pm
Rick Kane
The Ptolemic theory for the apparent movment of Sun, Moon, planet, and stars around the Earth explained most of the apparent movement, but inaccuracies in measurements caused Coperinicus to propose a heliocentric system. Only with Tycho Brahe did measurements and discepancies in measurements cause science to reject perfect celestial spheres, but Tycho himself remain a believer in a geo-centric universe/solar system http://en.wikipedia.org/wiki/Tychonic_system. Right now there is no interested party who wants to perversely contest the facts heliocentric solar system, but there are many interested parties who contest biological evolution and human influence climate change, both of which are “facts”, as Stephen Jay Gould defined the term, a thing that is “confirmed to such a degree that it would be perverse to withhold provisional assent.” Similar, certain economic facts, such as contraction of Goverment spending lead would lead to a contraction of the overall economy, are denied for perverse, self-interested reasons.t
Wednesday ~ September 14th, 2011 at 10:14 am
teageegeepea
On most days of the week I would side with both you and Robin in an argument with Russ, but here I think he has a point. There are measurements rather than forecasts of stimulus impact. John Taylor and Garrett Jones also did after-the-fact analyses. But Mark Zandi’s model incorporates no new facts after the actual passage of the stimulus. Physics also has areas when things are expected in advance of evidence (Karl Popper would argue that’s an essential part of science), but afterward the evidence is supposed to be compared against the theoretical predictions.
Wednesday ~ September 14th, 2011 at 1:43 pm
Bob Murphy
C’mon Karl, those aren’t the same types of measurement problems. It’s not that the number of jobs created is “out there” and we are trying to observe it, but we have to do so indirectly.
Rather, we are comparing the number of jobs existing with what we think would have happened, had there been no stimulus.
I understand that you can get really hardcore and say, “There is no ‘out there’ out there, it’s all in your mind man.”
Still, at best you could say the econometrics study is like asking, “How far would it be to the sun, if Jupiter turned into a small black hole for 3 minutes and then turned back?”
Wednesday ~ September 14th, 2011 at 11:38 pm
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