Skeptonomics

The New York Times reports that Europe is gradually approaching the point of decision on whether to allow genetically modified corn. Because of WTO rules on such things, the EU is required to base its policy on “science” if it want to keep out mutant corn from the US. This reflects a deep, deep misunderstanding of what science can contribute to policy.

Let’s start with the basics. There are two sorts of error we can make in this uncertain world, Type I (the risk of believing something to be the case when it is not) and Type II (the risk of not believing something to be the case when it is). Science is, among other things, a human enterprise organized around the systematic minimization of Type I error. Experimental protocols are about this, and so are the conventions we follow in determining statistical significance. This obsession comes at the cost of permitting greater Type II error, but that’s OK. Science operates on the basis of a vast division of labor, where each scientist’s work depends on the reliability of the methods and results carried over from what others have done. One false conclusion, if not noticed in time, could invalidate the efforts of an entire research community. This is why a serious Type I error is a potential career ender, whereas an avoidable Type II glitch simply diminishes a researcher’s list of accomplishments.

This single-minded insistence on avoiding Type I error is the reason why science is the one truly progressive human activity. Today’s science is better than yesterday’s, and tomorrow’s will be better than today. You can’t say this about poetry or politics.

(It is also, in the end, why economics is not a “real” science: it is no big deal for an economist to claim something to be true and to later discover that it isn’t.)

Policy, on the other hand, has to take Type II error as seriously as Type I. Take the Bt corn case before the EU, for example. It is a problem if regulators falsely think Bt corn is dangerous and ban it, but it is also a problem if they falsely think it is not dangerous and allow it to be used. A reasonable first cut is the standard cost-benefit approach: value each sort of error in terms of its cost function. Thus the cost of banning Bt corn is the probability of Type I error (falsely believing it to be harmful) times the economic cost of not taking advantage of this technology, whereas the cost of not banning it is the probability of Type II error times the cost of the damage it would do in that case. You go for the lowest cost option.

(There is an even better approach, as I argued here, based on the fullest possible utilization of information.)

The difference should be obvious. Science is radically asymmetric in the way it treats uncertainty: avoiding a false positive is everything. Policy is more balanced: failure to see is potentially as harmful as seeing what isn’t there. If you happen to be the sort of person, as I am, who thinks environmental risks are particularly important to avoid, you might tilt the policy calculus on issues like Bt corn toward less Type II error, even at the expense of more Type I.

Science has one job to do. Policy has another. They follow different rules.

I’ve been asked to review an article using computable general equilibrium (CGE) methodology. I’m likely to decline, but before I do I want to ask the vast universe that follows this blog: is there any defense against the argument that CGE and its offspring (DSGE) are simply bad economics?

There are two arguments actually:

1. CGE is an attempt to implement empirically a model that has been blown away theoretically. For 30 years we have known in precise terms why representative agent GE models are hogwash. We also know that the conditions for unique solutions are impossibly restrictive. Finally, while we have models that can translate modern, post-utility understanding of economic behavior into functional form, to do this throughout an economy, in every nook and sector, would be a gargantuan, and probably pointless, project. To put it bluntly, CGE modelers take as their starting point refuted theory.

2. CGE is false empiricism. It claims to generate results based on real-world data, but testing is nil, and I mean nil. Is there any literature out there I have missed in which past models are examined retrospectively against actual economic outcomes? If not, where is the falsifiability?

I will wait to send my rejection email. Maybe one of you can convince me that it is worth a few hours of my time to promote “better” CGE work.

In recent election cycles the term “populist” has been applied to such varied figures as John Edwards, Mike Huckabee, Patrick Buchanan, and Ross Perot, arguably sharing a sort of economic nationalism for the poor. Originating in anti-aristocratic agrarian movements in Europe, especially the Russian Narodniki of the late 1800s, the movement in the US attempted to encompass the urban working class as well, as symbolized by the rural Scarecrow marching along with the urban Tin Woodman on the Yellow Brick Road to defeat the Wicked Witch of the East, with populist heroine Dorothy and the Cowardly Lion stand-in for fundamentalist and anti-imperialist populist William Jennings Bryan, he of the “Cross of Gold” speech, in Baum’s populist fantasy novel. The movement would be partly absorbed by the later Progressive and New Deal movements.

The movement has always had a deep divide, with race the central issue. So, on the one hand we have the progressive wing, symbolized by the remnant Democratic-Farmer-Labor Party of Minnesota and the presidential candidacy in 1948 of FDR’s former Ag Secretary, Henry Wallace for the Progressive Party. On the other, in the Deep South, we got “Pitchfork” Ben Tillman in South Carolina, whose follower, Strom Thurmond, would run as the “Dixiecrat” in the 1948 presidential campaign. Today, this divide most clearly shows up in the struggle over immigration.

Credit markets are all a-jitter again. No one knows how many assets will be nonperforming, which ones they will be, how much total value is at stake. We also know that there has a been a sudden stop, a complete cessation of net long-term private capital inflows to the US; nearly all of the financing burden of the US current account deficit has to be shouldered by central banks and sovereign wealth funds. These two events are related.

It is US debt, mortgage items but perhaps not only, whose quality is in doubt. This is why there is little appetite for such goodies among private investors. But if enough liquidity is pumped in to dissuade investors from wholesale dumping, and if the CB’s continue to do what it takes to keep the dollar afloat, we may continue to muddle through.

The risk is that the two dangers will interact. The Fed and its partners can support asset values by buying into these markets, as they have indicated they will. But if for any reason this effort falls short, it is possible that default risk and currency risk could spiral upward in tandem. Fear of default could push private capital flows into the red; this would ramp up the pressure on the dollar, increasing currency risk, and so on. It is not beyond the realm of the possible that this nasty synergy could erupt within the time frame of a few hours or even minutes. It would be sudden and unexpected: one morning you could go online to scan the headlines and find out we were already in the thick of it.

I’m not saying that a crisis is inevitable, but I’m not saying it can’t happen either.

The eco-elite have descended on Bali to devise a successor regime to the Kyoto Protocol. I think most of them are asking the wrong questions and are likely to come up with the wrong answers.

To begin with, we should be clear on what the limitations of Kyoto are. They are not primarily the weak targets that were set for carbon reduction, nor were they the forbearance shown to developing countries. Why not?

The targets proved not to matter because they have not been met. In fact, there is no way at present to force a country to act decisively on curbing greenhouse gases, so discussion of specific targets is a sideshow. In any case, no country should pull back from taking aggressive action because an international treaty sets the bar several notches lower.

For the same reason, it was never a problem that Kyoto exempted low income countries from the expectations put on the industrialized world. Aside from the question of equity – climate change is driven by accumulated emissions, most of which came from us and not them – there is no way to force a country like China or India to make its development conditional on reaching carbon goals.

The one thing Kyoto did that “worked” shouldn’t have, carbon offsets. The evidence shows that much of the offsets actually offset nothing at all: they are fictitious carbon reductions. And others take money to mitigate one environmental hazard by creating another, like tree plantations that replace living forests.

So the first thing an enlightened eco-diplomat in Bali should understand is that Kyoto should not be fixed; it should be scrapped. I appreciate its symbolic value, but surely the time for symbolism is past.

What to do then? The starting point for reasonable negotiation is the awareness that the majority of the world’s people will be direct financial beneficiaries of controlling climate change, if the job is done properly. Any country that sets up a system of carbon permits, auctions them off and rebates the money to its citizens on a per capita basis will find that most will come out ahead. This is because climate-bashing consumption is disproportionately done by the rich. Make them pay for it, and distribute the proceeds equally; the lower- and middle-consumption majority will get back more than they pay in. To put it another way, societies have been giving away their crucial environmental resources, like the atmosphere in its role as a waste sink, for free to anyone who wants to take them. Charging a price puts money in the pockets of the owners – us.

Implication: we don’t need a global treaty for countries to set up serious carbon emission controls. That’s not what Bali should be about.

What it can do are two things. First, by far the most efficient point at which to control carbon is where it enters the economy, as oil, coal or gas at the mine or wellhead. This is far less complicated than trying to track it down in its myriad uses, and it leaves the fewest loopholes. For any individual country this will mean requiring permits to bring fossil fuels across the border. Negotiators of a new international framework can work to standardize these permits, so that their markets can be international. This would minimize disruption to cross-border economic life. (I’m a rootless cosmopolitan and favor this sort of thing.)

The most important topic to discuss, however, is how to insulate national economies from the possibility that carbon control could raise domestic costs of production, hurting domestic producers in international markets. (Yes, I know the argument from trade theory that says this is not a problem, and no, I don’t believe it.) It is becoming clear that this will have to take the form of carbon adjustment tariffs (CAT’s), something I weighed in on a few posts back. I think there is a real risk that lobbyists would swarm all over the process of deciding how large a tariff is needed to offset carbon cost differences, and that an internationally negotiated schedule would have more integrity. That, more than anything else, is what Bali should be about, setting up a framework for negotiating such tariff schedules, so that each country can decide for itself how aggressive to be in carbon policy without worrying about getting too far out front.

What Bali should not do is convey to anyone anywhere that local or national action has to wait until a worldwide consensus has been reached.