This kind of debate is absolutely and endlessly fascinating to me. Go ahead, read ‘em all. I’ll admit that the original Landsburg example was very counter-intuitive to me, even though I generally agree with him. But that’s not the interesting part — it’s that there is such an amazing divide. And not a polite one either, Krugman actually implies that Landsburg doesn’t really deserve his Ph.D.
That there can be such a debate over (what seems to me) to be a very basic principle of the field is totally astonishing. Physicists might argue over whether string theory is valid or not, but that’s pretty advanced stuff — they all basically agree on how simple stuff like inclined planes work. Now, I understand that there are no political implications in the area of inclined planes — if there were, (is friction conservative or progressive?) there might be more debate. But even in fields with heavily charged issues — take climatology or evolutionary biology — the tendency seems to be for the field to develop a consensus and then mock the outsiders who disagree. But this seems to be a pretty bedrock disagreement amongst a number of well-respected (though politically opposed) industry insiders.
This seems to have pretty scary implications for the science. And even if the debate is not over the actual theory and definitions, but rather over the potentially implied policies of that theory, that brings up an equally uncomfortable conclusion: that at least one side of this debate thinks that the theory must be presented in a way that supports their policy goals.
I really wanted to title this post: “Fifteen Men on a Dead Man’s Tax Forms.”
Via Steven Landsburg, I see that Paul Krugman has essentially resorted to third-grade level statistics. Take it away, Paul:
I’ve been getting some mail over yesterday’s column, with angry correspondents posting charts like this, showing government spending as a percentage of GDP, to claim that government spending has too surged:
He says this is dishonest, since:
What’s going on? Yes, that’s right: it’s what happens when you divide by GDP in a time of terrible economic performance. Spending hasn’t surged; in fact, it grew more slowly in the two years after Lehman collapsed than in the two previous years, despite a sharp rise [what's the difference between "a surge" and a "sharp rise" -- apparently Krugman knows] in spending on safety-net programs. Instead, GDP growth has plunged.
This is a totally fair critique — you could show a surge in spending even with a decline in real dollars spent, if GDP had dropped enough — and of course is has dropped over the last 2 years. But here’s where the mindboggling, balls-out dishonesty comes in. Here’s the graph that Krugman posts to refute it:
But if you look at the raw numbers on government spending, here’s what you see:
I’ll take a moment to pause, because everyone who has ever taken a stats course or submitted a research paper has just violently thrown up on their computer screen. What Krugman’s done here is completely unacceptable — he just compared two graphs, after resizing the Y axis. This is 100%, totally, fundamentally dishonest.
Yes, I know that what he said he did was get a graph that showed real spending increases vs. spending-as-a-percentage-of-GDP and he did indeed do that — but the problem is that if that was all he did, the graphs wouldn’t look the way he wanted them to — the 2nd would actually show a larger change (see below), with similarly scaled Y axes. But when he resized the Y, he’s stepping into cheating land. To get a good grasp of how dishonest this is, you have to look at the actual numbers.
The top graph which, according to Krugman, dishonestly shows “a surge,” has a total increase (going purely on my visual estimations, instead of referencing the actual numbers, since Krugman is asking his readers to rely solely on the graph) of ~30.8 to 36.1 — the latter number is about 117% of the former. In the lower graph, the left most number is ~4,100 and the final number about ~5,300, which is about 129% of the former. I’ll let that sink in. Krugman has “refuted” his opponent’s claim of there being a “surge” in government spending by reproducing a different graph with a method of calculating spending that actually shows a higher percentage increase — which, no matter the subjective definition of “surge” or “sharp rise,” I think we can all agree that 129% of something represents a larger “surge” than 117% of something.
The entire reason the second graph looks like a less drastic increase is the resizing of the Y axis, which is completely dishonest. I feel like a broken record, but this is simply unacceptable. You can’t do that and expect to be taken seriously. To get a good feel for how crazy Krugman’s claim that “real spending vs % of GDP shows there was no spending surge” is, you have to understand that it’s usually the “cut spending” (i.e. Krugman’s enemies) crowd that revises the graphs like this — there’s a reason Nick Gillespie, in his “we are out of money” rants at Reason.com, always encourages using the real dollar amounts, because it makes the spending increase look larger!
This is flat out dishonesty.
I know everyone’s already jumped on it, but I think the funniest part about this short Krugman post is that in all the years he’s advocated liberal government policies of his own, he never once would’ve allowed some critic of them to say:
And don’t say that we just need better politicians. If [liberalism] requires incorruptible politicians to work, it’s not serious.
So why is it a legit critique of libertarianism, a philosophy which emphasizes less power for those corruptible politicians? He hilariously actually thinks this “but what about corruptible politicians, eh?” is a good argument (I guess, why else would you put on the NYT for everyone to see?) but he hasn’t found a need to deploy it over his entire career, until now — as an argument against… people who advocate granting less power to politicians. What someone needs to do is a Daily Show-esque Krugman v. Krugman debate, where every time he presents some idea, Krugman 2 responds with “but if it’s dependent on corruptible politicians, it’s just not serious!”
The really sad part is, Krugman is supposed to be the vanguard of liberal policy thought. And this is the kind of debating acumen he’s displaying? There actually are thorny government capture problems (well, certainly moreso than the one he presents) with which you can challenge libertarians — like say the corruptibility of the government in spheres everyone admits are necessary, like the military or the courts. But to say the libertarianism doesn’t work because the government passed a law that regulation-averse libertarians don’t think they should have the power to pass — is just pathetic.
This is getting kind of embarrassing — I feel like I’m making a strawman argument, because I couldn’t actually imagine that a liberal would be so dense as to really say “the fatal flaw in libertarianism is dependence on incorruptible politicians” — yet there’s Krugman saying it on the NYT. I guess sometimes you get a freebie.