On the Correlation Between Crime and Punishment

In two previous posts (here and here) I've taken a look at the OECD's 50^th anniversary present to all of us - their "Better Life Index" (BLI). One of the eleven components of that Index is titled "Safety" - and according to the OECD this component

"...... largely reflects the risks of people being physically assaulted or falling victim to other types of crime. Crime may lead to loss of life and property, as well as physical pain, post-traumatic stress and anxiety. The biggest impact of crime on people’s well-being appears to be through the feeling of vulnerability that it causes."

The BLI site also notes that

"Across the OECD, one person in six reported falling victim to a conventional crime, with physical assault accounting for nearly a quarter of all conventional crime. In terms of perceived safety, one out of four people in the OECD report feeling unsafe on the street after dark."

In addition, the average homicide rate across the OECD countries is 2.2 murders per 100,000 inhabitants.

An interesting question that arises is whether or not the relative safety level matches the relative incarceration rate.

Obesity, Driving, & Unbalanced Regressions

The Economist magazine's daily chart of 15 June 2011 was to do with a recent study on the relationship between obesity and amount of driving. This study is reported in a paper by Jacobson et al. (2011), which is "in press" at the journal, Transport Policy. This paper will bring tears to all econometric eyes! Not tears of joy, either.

There are so many things that one could say about it that it's really difficult to know where to start - but I'll try!

Before we start, though, a word about the charts in the 15 June chart blog in The Economist. There are two of them - look at the one on the left. Are they really plotting the correlation between the two variables in question? I don't think so.  Anyway, that's not my real gripe. My problem is with the paper that's being published by Transport Policy (TP). And judging by the nature of the comments on The Economist's blog, I'm not alone.

From its website, I see that TP has an impact factor of 1.024. This just goes to show how misleading impact factors can be - it's quite possible to get the impact factor above unity simply by publishing material that infuriates people so much that everyone has to cite it in order to take issue with it! Nice trick if you can get away with it!

Google Correlate

There's an interesting piece in the latest issue of The Royal Statistical Society's newsletter, RSSNews. It's about one of Google's new data analysis tools, called Google Correlate. If you haven't come across this, it's worth a look.

You can upload your own time-series data (from a .csv file, say) and then use Google's search history to find what other data your series correlates highly with.

Just keep in mind that "correlation" and "causation" are not the same thing! More on the latter in future posts.

© 2011, David E. Giles

Testing for OPEC-Causality

Last Friday, the OPEC meeting being held in Vienna broke up in what has been widely described as "disarray". A group of OPEC members, led by Iran and Venezuela, vetoed plans for an increase in the world production of oil. Think of the words "supply", "demand", and "elasticity". and you can guess what they were thinking.

Saudi Arabia then announced that it would step up to the plate and increase its production to meet world demand. It'll no doubt be assisted by some of its Gulf allies.

OPEC was founded in September 1960, with 5 member countries. Today, this cartel has 12 members - Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela. Yes, make no mistake about it - OPEC is literally a cartel. It determines the supply and price of crude oil. Let's take a closer look.

Type I Errors in Economics Publishing

"Economists are peculiar social scientists not least because they attach enormous value to the publication of articles in the refereed journals and virtually no value to the publication of books. It is difficult for economists to have a coffee break without a conversation which quickly turns to questions like: "Why was my article refereed by so-and-so journal? Why did the anonymous referees say what they did? Where shall I send my next paper?" In short, the publication process merits a hideous fascination if only because it governs the pecuniary and non-pecuniary rewards of the economics profession."

Sound familiar?

This quote is taken from the blurb (product description) for the book, Publishing Economics: Analyses of the Academic Journal Market in Economics, edited about a decade ago by Joshua Gans. This book contains fifteen great articles that still highly relevant, and should be required reading for all young econometricians.

Joshua, and his former Stanford class-mate, George Shepherd, wrote a great article (Gans and Shepherd, 1994) providing us with tales of rejection from many eminent economists. Econometricians can take heart from the fact that the list includes James Tobin's unsuccessful attempts to get his work on the Tobit model published in Journal of the American Statistical Association (the statisticians' equivalent to the AER.)

The material gathered in preparing this paper was subsequently edited by George into the book, Rejected: Leading Economists Ponder the Publication Process. Again, an except from the product description does a better job than I could:

"Many people know that Robert Merton and Myron Scholes won the 1997 Nobel Prize in Economics for their now famous 1973 paper on options pricing. A lucky few are aware that this options paper was rejected by several leading journals before the Journal of Political Economy finally accepted it. This book compiles tales of rejection from more than 70 leading economists, including 20 Nobel winners."

The tales herein are a great read. Especially if you've recently received a rejection letter!


Note: The link to the following reference will be helpful only if your computer's IP address gives you access to the electronic versions of the publications in question. That's why a written Reference section is provided.

Reference

Gans, J. S. and G. B. Shepherd (1994). How are the mighty fallen: Rejected classic articles by leading economists. Journal of Economic Perspectives, 8, 165-179.

© 2011, David E. Giles

Feeling Rejected?

Earlier this week I had a request to become a "contact" for a particular person on LinkedIn. As this didn't appear to be someone I knew, I was about to press the "Delete" button when I had this strange feeling that the name was just slightly familiar, after all. And then I remembered.

As Editor, or Associate Editor, of an academic journal, you occasionally get to see the darnedest things - and I don't just mean the things that are submitted! I'm referring to the dark underbelly of academia. That place where your supervisor should have warned you never to go. I have a number of editorial responsibilities right now, including being joint Editor of The Journal of International Trade & Economic Development. This year alone I've been saved on two occasions from making a bad mistake (and possibly getting our publisher involved in a lawsuit), only as a result of eagle-eyed referees. Hopefully, there aren't even more cases that I'm unaware of!

An Even Better Life?

Last week, in a post titled, It's a Wonderful Life, I discussed the OECD's recently released "Better Life Index" (BLI). The index is made up of eleven different components that are then aggregated, with equal weights, into a single BLI, which you can see here. In addition, the OECD provides an interactive tool so you can select your own weights across the 11 measures, and then make cross-country comparisons.

At the end of that earlier post I noted that one question that I hadn't addressed  was: "What's really driving the variability in the country rankings?" I promised to return to this question - so here we are.

Busking for Business

On World Statistics Day, 20.10.2010, the Royal Statistical Society launched its getstats campaign. This is a major drive to promote the statistical profession and the importance of statistics to the general population. It's a consciousness-raising venture that, as a Fellow of the RSS, I heartily endorse. Recently, the getstats campaign manager, Debra Hurcomb, has suggested that we should view this as a form of busking.

Now, taken literally, this appealed to me no end, and I thought immediately of the International Society for Bayesian Analysis (ISBA)  and their biennial meetings, which are famous for their highly creative cabarets. If you're not familiar with all of this already, you really should check it out at The Bayesian Songbook.

The Songbook should be on the "required reading" list of courses in statistical or econometric methodology. I certainly link to it on the web page I use when I'm teaching our elective graduate econometrics course - a course that includes both frequentist and Bayesian material. We don't actually have sing-along sessions in that course - given the quality of my singing, that would be one sure way to clear the room in a hurry.

The origins of the Bayesian Songbook can be traced to to George Box's wonderful song, "There's no Theorem Like Bayes' Theorem", to be sung to the tune of "There's no Business Like Show Business". It's a classic of epic proportions, and was first performed at the first ISBA Valencia meeting in 1979.

Just another instance of  Bayesians being ahead of the curve! As if we really needed more examples!

So, following the exhortations of the RSS, and the lead of the ISBA, it's just glaringly obvious that we should be out there promoting Econometrics with some creative and energetic busking. And we have a leader already! Guy Judge at the University of Portsmouth in the U.K. has been on to this for some time, so it's just a matter of getting in behind him! I'm particularly partial to his "Heteroskedasticity Blues"; and if (like me) you can't carry a tune, Guy also has a nice collection of Econometrics poems.

So, once more, from the top - with feeling!

© 2011, David E. Giles

Eliminating Inflation Through Creative Econometrics

The other evening my wife asked me if tulips are poisonous to cats. I didn't know the answer off hand. The question was prompted by the fact that our furry beast was attempting to graze in the remaining tulips on our patio. (Technically, it was attempting to browse, but that's O.K..) The same tulips I've been staring at for about 7 weeks now!

Here on the We(s)t Coast Spring has been longer, cooler, and more damp this year than any of us would care for. After a while it gets you down, and you feel as if the fog has actually penetrated your brain. Strange thoughts begin to surface, just when you least expect them.

The question about the cat and the tulips interrupted my own contemplation of a notice that I'd seen on campus earlier in the day. It concerned a summer course being offered by our Department of Linguistics here at UVic. namely LING 388: "An Introduction to Grammar of English Usage". I had been thinking that this was something I should recommend to some of our students - until I observed that it said at the bottom of the notice: "No Prerequisites Required." Isn't that third word redundant?

I warned you - this weather does bad things to your mind!

Zanran

Zanran is to data, what Google is to text.

Now in its Beta-testing phase, the new search engine, Zanran, seems certain to appeal to all of us who use data on a regular basis. Founders Jon Goldhill and Yves Dassas describe Zanran in the following way:

"Zanran helps you to find ‘semi-structured’ data on the web. This is the numerical data that people have presented as graphs and tables and charts. For example, the data could be a graph in a PDF report, or a table in an Excel spreadsheet, or a barchart shown as an image in an HTML page. This huge amount of information can be difficult to find using conventional search engines, which are focused primarily on finding text rather than graphs, tables and bar charts."

On 31 May I used Zanran to search "zero inflated Poisson" (see above), and returned 4,394 results, each linking to data in graphs and/or tables. Here are the first 5 items in the list:

When you "hover over" the pdf icons for each of the first three items above, here are the previews that you see:

Then, of course, if you like what you see, you just click your way to the linked document, be it a pdf file, an Excel worksheet, an HTML page, or whatever.

No, I'm not an investor, but this is one cool search engine. Try it - you'll love it!

(HT to Andrew Gelman.)

© 2011, David E. Giles