Posts Tagged ‘research’

Indexing of Technical Change in Aggregated Data

November 29, 2017

My latest publication is forthcoming in Computational Economics and can be accessed here: rdcu.be/yvm5. The abstract:

The Baltagi–Grifn general index of technical change for panel data has earlier been applied to aggregated data via the use of period dummy variables. Period dummies force modeling into estimation of the latent level of technology through choice of dummy structure. Period dummies also do not exploit the full information set because the order of observations within periods is ignored. To resolve these problems, I suggest estimating the empirical equation for all possible structures of the dummy variables. The average over the different dummy coefcient estimates provides an index of technical change. More generally, the method estimates a general, model-free trend in linear models. I demonstrate the method with both simulated and real data.
The paper is essentially a real simple idea that works well in many situations and solves a difficult problem. I came up with this idea while working on this paper, and can as such be viewed as a spin-off from that. I gather that methodological papers seldom are spin-offs from empirical apply-this-different-method-to-this-data papers, but that is what happened here. I am quite proud of this paper and regard it as my most innovative and important contribution so far. What surprises me most is that, from what I can tell, no-one seems to have thought of this simple idea before.
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ARC-Change web page

October 26, 2016

Earlier this year, I posted on a new research project, ARC-Change, on climate change in the Arctic and its consequences for governance and resource industries. The project is now underway, and recently the project web page went online (click logo below to go to the site).

arcchangelogoboxfish

New Research Project on Climate Change and the Arctic

April 5, 2016

I will take part in a new research project on climate change in the Arctic. The project carries the long name “ARCtic Marine Resources under Climate Change: Environmental, Socio-Economic Perspectives and Governance,” or ARC-Change for short. From the project description:

As we enter the Anthropocene, climate change moves the parameters we live within. First and foremost, these changes will take place in Arctic regions, regions that already are subject to substantial, large scale natural variability and where higher temperatures and retreating sea ice will redefine boundaries of biological life, ecological structure, and commercial and social opportunities. Complex interactions and causal mechanisms exist from the physical impact, in terms of temperature, ocean currents, via biological and ecological adaptations, in terms of habitat expansion, growth conditions, species interactions, via social and business enterprise, in terms of new fishing areas, trade routes, mineral wealth, to governance implications, in terms of pressure on existing agreements on fishing, surveillance, and commercial activity. A cross-sectorial and cross-disciplinary perspective is needed to investigate and understand climate change impacts. ARC-Change will study some of these interlinkages, from the physical and biological to the economical and governmental, while brining together expertise from an array of disciplines and institutions.

More in the press release.

Update: The ARC-Change webpage.

The postdoc dilemma

April 25, 2012

A while ago, I read a column in Nature which I related to. Like the author, I am currently a postdoc researcher, and recognize the dilemma. The column ‘The postdoc dilemma’ appeared in the Careers section and was written by Gaston Small. The crux of the dilemma:

The job–career balance is a fundamental challenge for postdocs. Fulfilling the obligations of the project that currently pays your salary is, of course, essential, but at the same time postdocs need to push previous work through the publication process, which often entails multiple revisions. Writing grant applications, and applying and interviewing for faculty jobs are necessary activities; […] postdoc funding runs out quickly. These additional responsibilities to our careers are as time-consuming as obligations to our full-time jobs.

An important point made in the column is that in the postdoc will work on papers from the postdoc project in years after the project is over and thereby catching up on whatever time lost on non-project work.

 

 

Journal Submission Strategies

October 27, 2009

What sparked this post was a discussion with a fellow PhD-student, where I was told that advice from several senior researchers was not to submit a basically finished manuscript because it would have to go to an only okay journal; not a top journal. Instead, the manuscript should be totally reworked and then sent to a top journal. One top journal publication is supposedly more worth than five ‘other’ publications.

I don’t understand. Anyway, it motivated me to read a recent article from the B.E. Press by Heintzelman & Nocetti on journal submission strategies. The article starts out with two quotes from famous economists:

Start with a higher-quality outlet than your eventual target […] The professional returns to choosing a better journal are higher. But a strategy of aiming high requires thick skin; the acceptance rate at major economics journals is around 10 percent. Thus, it pays to have a ‘submission tree’ in mind, a sequence of alternative outlets for your work. – Daniel S. Hamermesh [see Heintzelman & Nocetti 2009 for the reference]

Give each of your papers a shot or two at the top journals, such as the AER, JPE, or QJE. Even if you are not confident in the paper, it is worth a try for two reasons. First, as author, you are not in the best position to judge its quality; some people are too fond of their own work, and some are too hard on it. Let the editors decide. Second, the editorial process is highly imperfect. The bad news is that some of your best articles may end up getting rejected from the top journals. The good news is that you may get lucky, and some of your so-so articles may end up published in top journals simply because they hit the editor’s desk when he is in a good mood. – Gregory Mankiw [p. 1]

Fair enough; these advices does not say only to go for the top publications. More interesting, perhaps, is footnote 2 on page 2, which refers to ‘Oswald (2007)’ [again, see Heintzelman & Nocetti 2009 for the reference], which ‘shows that the best (most-cited) articles in middle-tier journals are often ‘better’ than the least-cited papers in top-tier journals.’

Heintzelman & Nocetti 2009 moves on to show that Hamermesh’s and Mankiw’s advices holds up well in their analysis.

Given the long reviewing times in most journals, however, [the advices] may not be well suited for young, untenured, professors who are more likely to be impatient and risk averse. These authors should instead consider submitting to lower tier journals first [p. 3].

And then move up the ladder?

Heintzelman & Nocetti also brings advice for less gifted authors (read: me):

[A]uthors of papers that are not of the highest quality, and especially those without an established reputation, will lean towards lower tier outlets [p. 3].

The part on reputation is somewhat unsettling. Anyway, the ‘senior’ advice my fellow student got seems to be B.S.

(Somewhat) related post:

Green Bias

August 13, 2009

Economists often tend to think of biologists as tree-huggers or similar kinds. Of course, there’s something to it. Most researchers tend to work on issues that interests them, and of course the ‘intrinsic’ interest is an asset in the research. The researcher works harder. But is it also a problem? But of course. It influences the research agenda, it may bias results. Maybe more importantly, are biologists aware of such problems? Do they care?

Sometimes, I suspect economists to kind of use the tree-hugger characteristic against biologists. Is it sometimes because biology is a proud memeber of the hard sciences? Something econoics, notably, is not, traumatically enough.

Last night, I talked to an ecologist about this. He agreed that there might be something to my agenda; the research agenda of biologists are often coloured green; they may end up with biased results. But, he contended, economists aren’t necessarily any better. (He’s seen a lot of [environmental] economists make biological claims that are plain wrong!) He’ s probably right. People tend to what they care for & care for what they tend to.

What kind of bias does the ‘intrinsic’ outlook of the economist introduce? (I don’t know; I am [supposed to be] one. Is it blinding to care about efficiency & trade-offs?)

The ecologist slid off the hook, though. Economists doing the same mistake doesn’t free the biologists of guilt.

Unintended Consequences of the Endangered Species Act

May 15, 2009

I’ve posted on research on the Endangered Species Act earlier. Yesterday, Freakonomics’s Stephen J. Dubner mentioned an earlier post of theirs which discusses the unintended consequences of it (Dubner draws a parallel to other protective laws with similar unintended consequences):

Consider the Endangered Species Act (E.S.A.) of 1973, which protects flora and fauna as well as their physical habitats. The economists Dean Lueck and Jeffrey Michael wanted to gauge the E.S.A.’s effect on the red-cockaded woodpecker, a protected bird that nests in old-growth pine trees in eastern North Carolina. By examining the timber harvest activity of more than 1,000 privately owned forest plots, Lueck and Michael found a clear pattern: when a landowner felt that his property was turning into the sort of habitat that might attract a nesting pair of woodpeckers, he rushed in to cut down the trees. It didn’t matter if timber prices were low.

This happened less than two years ago in Boiling Spring Lakes, N.C. “Along the roadsides,” an A.P. article reported, “scattered brown bark is all that’s left of once majestic pine stands.” As sad as this may be, it isn’t surprising to anyone who has examined the perverse incentives created by the E.S.A. In their paper, Lueck and Michael cite a 1996 developers’ guide from the National Association of Home Builders: “The highest level of assurance that a property owner will not face an E.S.A. issue is to maintain the property in a condition such that protected species cannot occupy the property.”

[…]

In a new working paper that examines the plight of the cactus ferruginous pygmy owl, the economists John List, Michael Margolis and Daniel Osgood found that landowners near Tucson rushed to clear their property for development rather than risk having it declared a safe haven for the owl. The economists make the argument for “the distinct possibility that the Endangered Species Act is actually endangering, rather than protecting, species.”

The article concludes: “…if there is any law more powerful than the ones constructed in a place like Washington, it is the law of unintended consequences.”

Stay tuned and I will use that exact quote from the List, Margolis and Osgood paper in my own research!

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