April 29, 2024

Today’s Economist: Nancy Folbre: The Science of Prophets and Profits

Nancy Folbre, economist at the University of Massachusetts, Amherst.

Nancy Folbre is an economics professor at the University of Massachusetts, Amherst. She recently edited and contributed to “For Love and Money: Care Provision in the United States.

Some say economics is not a science at all, because it doesn’t successfully predict the future. Others point accusingly at a lack of unanimity. Many construe fierce political convictions as a sign of bias.

Today’s Economist

Perspectives from expert contributors.

Wrong on all three counts. Both science in general and economics in particular are much more interesting than these formulas imply. The meetings of the American Economic Association and the larger umbrella of organizations in the Allied Social Science Association in San Diego in early January offered plenty of examples.

Seldom can any science accurately predict the future. In a region particularly susceptible to earthquakes, it’s impossible to say when and how cities like San Diego will be shaken. Sea levels are rising as a result of global climate change; no one knows exactly when they will flood the first floor of the luxury hotels.

Many economists, themselves, long for unanimity. One paper, “Views Among Economists: Professional Consensus or Point-Counterpoint?” by Roger Gordon and Gordon B. Dahl of the University of California, San Diego, presented at a session on “What Do Economists Think About Public Policy Issues?” used data from a regular survey of economic experts to assert that opinions differed little as long as extensive research was available.

In another paper at the same session, “Comparing Beliefs of Economists and the Public,” Luigi Zingales of the University of Chicago, asserted that public opinion is least swayed by economists when economists are largely in agreement.

Two discussants – both with strong claims to economic expertise – begged to differ with the first of these presentations.

Paul Krugman of Princeton forcefully asserted that disagreements regarding macroeconomic policy are momentous. Justin Wolfers, currently at the University of Michigan, offered a sharp and funny analysis of policy differences between “Team Blue” and Team Red” among surveyed experts, acknowledging that, in some cases, he used Facebook pictures to infer political affiliation. His analysis got even more laughs from the audience than the official humor session on Friday night.

A voice from the audience complained that the expert panel survey, assembled by the University of Chicago’s Booth School of Business, was limited to about six faculty members from each of the seven “most elite research universities in the U.S.” The session organizer seemed taken aback by the very possibility that any respectable economist might feel unrepresented by such eminences.

Differences among economists teaching at elite research universities and others are probably quite significant and deserve attention in survey research.

These differences of opinion don’t signal immaturity or inadequacy in scientific endeavors; they are a driving force of scientific progress. As the well-known philosopher of science Thomas Kuhn explained, dominant paradigms typically become encrusted and resistant to change, making it difficult for their adherents to even perceive anomalies that are inconsistent with existing theory.

Burgeoning research in behavioral economics speaks to this issue, pointing to many examples of putatively rational consumers behaving in distinctly irrational ways. So-called framing effects influence the way everyone, including scientists, interpret information. Sometimes the only way to see how one is implicitly framing a problem is to face a direct challenge from someone who frames it completely differently.

The late Professor Kuhn contended, even more assertively, that older scientists almost never relinquish a theoretical frame, but are, thankfully, eventually replaced by a younger generation that has smaller intellectual investments in the status quo.

Some economists are probably convinced that their own views, however imperfect, are more accurate than those of the public at large and that more unanimity (even if slightly forced) would increase the profession’s policy impact. They should, instead, consider how fully discredited the profession would be if all its members (rather than just a few leading lights) agreed on a policy measure that turned out, in retrospect, to be completely incorrect.

In other words, there are benefits to a diverse portfolio.

As Professor Zingales pointed out, the carbon tax, which most surveyed economists favor (as do I), is so disliked by voters that politicians of both parties are loath to raise it.

Political allegiances are clearly linked to theoretical frames. Knowing whether someone leans left or right is often makes it possible to predict where they stand in economic debates. But it does not follow that those who clearly or even vehemently state their allegiances are somehow more biased than those who don’t.

Trying to evenly split the difference between left and right defines a path that is about as predictable as either of the extremes – and heavily influenced by both.

Better to have differing views debated openly and to identify all sources of financial support for research. To its credit, the American Economics Association just officially adopted conflict-of-interest rules, as Ben Casselman wrote in The Wall Street Journal, “in response to criticism that the profession not only failed to predict the 2007-8 financial crisis but may actually have helped create it.”

Economists can’t vow impartiality. But they should always reach, with humility, for the truth.

The Marxist historian E.P. Thompson put it this way: “The evidence is there, not to disclose its own meaning, but to be interrogated by minds trained in a discipline of attentive disbelief.”

Article source: http://economix.blogs.nytimes.com/2013/01/14/the-science-of-prophets-and-profits/?partner=rss&emc=rss

Scientists Say Atlas Is Wrong on Greenland’s Glaciers

Not the way climate scientists see it.

“Fiasco” was the word chosen by one scientist in an e-mail to the National Snow and Ice Data Center in Boulder, Colo., alerting his colleagues to erroneous claims made by the publishers of the atlas (whose name derives from The Times of London) about the speed at which Greenland’s glaciers are melting.

He also feared that a map in the atlas, along with news accounts repeating an error in the news release, could pull climate scientists into another vortex of damaging controversy.

The news release, echoed by the news media, claimed that Greenland had lost 15 percent of its permanent ice cover from 1999 to 2011. That translates to 125,000 cubic miles, according to a rough calculation by Etienne Berthier, a glaciologist with the University of Toulouse, enough melted ice to raise sea levels three to five feet.

The corresponding map in the atlas itself indicated that significant portions of Greenland’s coastline had become ice-free.

Glaciologists, previously bruised by an exaggerated claim about the melting of Himalayan glaciers in a 2007 United Nations report that became fodder for global warming skeptics, mobilized as a truth squad.

On blogs, on radio programs and in newspaper columns, they stated emphatically that Greenland has not lost 15 percent of its ice cover in recent years. The retreat, they said, is more like one-tenth of 1 percent. They were quick to add that nobody at the atlas had consulted them.

“It was a case where, really, the community came together really fast with both barrels blazing,” said Mark Serreze, director of the snow and ice center in Colorado. “Everyone had some real bad memories of this whole fiasco that had to do with Himalayan glaciers. No one wanted to see that again.”

The glaciers error in the 2007 report by the Intergovernmental Panel on Climate Change on Climate Change, although just a footnote, led to a torrent of criticism focused on climate scientists after it was identified early in 2010.

The HarperCollins subsidiary Collins Geo, publisher of the Times atlas’s 13th edition, has apologized for the news release and says it is “urgently reviewing” the map of Greenland. But for critics, its backtracking was a little slow — comparable, perhaps, to the actual rate at which Greenland’s ice is melting.

The news release and the atlas went public just after midnight on Sept. 15, a Thursday. Throughout the weekend, scientists were energetically challenging the error and trying to get their own information out.

By Monday, ScienceInsider, an online supplement to Science magazine, was reporting on the “outraged” scientists’ efforts. HarperCollins fired back at the scientists in a statement that was quoted that day in the newspaper The Guardian.

“We are the best there is,” an unidentified Harper Collins spokeswoman said. “We are confident of the data we have used and of the cartography.”

“We use data supplied by the U.S. Snow and Ice Data Center in Boulder, Colo.,” she went on. “Our data shows that it has reduced by 15 percent. That’s categorical.”

Theodore Scambos, a glaciologist at the center, set out to reverse-engineer the error. His best guess, after a foray into cartographic forensics, was that a mapmaker at the atlas had mistaken a center’s map of the ice’s thickness for one showing its extent.

In an e-mail on Friday, however, Sheena Barclay, the managing director of Collins Geo, said that was not what happened. But she did not say how the confusion arose.

The map of Greenland in the new edition shows significant portions of coastline in colors indicating land, as opposed to the white that denotes ice. “They’ve basically erased hundreds and hundreds of glaciers around Greenland,” said Poul Christoffersen, a glaciologist at the Scott Polar Research Institute in Cambridge, England, who praised the truth-squad effort. “It looks like the ice sheet is 100 kilometers,” or roughly 60 miles, “from the coast, whereas several glaciers are terminating right into the sea.”

On Thursday, Ms. Barclay said on a BBC radio news program that the Greenland map in the atlas would be reconfigured with the help of scientists, although she did not say the current one was wrong. She promised a new, “much more detailed map of Greenland that will represent more effectively the ice cover as it is.”

Asked if by “effectively” she meant “accurately,” Ms. Barclay replied, “It’s a case of actually how you define the ice itself, and at the scales at which we show Greenland it’s actually quite difficult to achieve that.”

Article source: http://feeds.nytimes.com/click.phdo?i=de5a038b40923abe44b07fa72dc99e0f