Wronging rights

Kate has a B.A. in Genocide from NYU's Gallatin School. Amanda has a Masters Degree in Violence, Conflict, and Development Studies from SOAS at the University of London.

These girls have some seriously wicked education, and they author the highly recommended wronging rights blog. Their special skills: crimes against humanity, modern warfare, and the social construction of atrocity. It's a delight to read.

Postscript: As a bonus, the top post right now comments on yet another horrid BBC news story - and as loyal readers of this blog know, I NEVER get tired of stories pointing out how abysmally bad the BBC is and imply I should be getting my license fee back.

Greg Mankiw is up to no good

Greg Mankiw comments on why he is not interested in heading the NBER:

Why did I decide not to pursue the job? As in many such decisions in life, various factors were at play, both personal and professional. But what really pushed me over the edge was pending tax policy. With the Bush tax cuts set to expire in a couple years, I am looking for ways to reduce my taxable income.

He also quotes a paper by Martin Feldstein, the outgoing NBER head, which sheds light on what Greg intends to do:

A change in individuals' marginal income tax rates can induce them to alter their taxable income in a wide variety of ways, including:

1. changes in labor supply,
2. in the form in which employee compensation is taken,
3. in portfolio investments,
4. in itemized deductions and other expenditures that reduce taxable income, and
5. in taxpayer compliance.

If my interpretation of Greg's statement is correct, the driving force behind his decision is not to increase the amount of leisure he consumes: he doesn't want to substitute some leisure for income, he is looking to reduce his taxable income. So 1 is out.

3 is also out, as it is not a labour market response and it is independent from his decision to take the NBER job. Four is largely independent of labour market decisions as well. This leaves us with 2 and 5, and 2 is in most cases nothing other than a soft version of 5.

So Greg's plan is to invest more resources in cheating the taxman, which is at best morally ambivalent and at worst outright illegal.

Furthermore, it is notesworthy how he takes this opportunity to make a political statement. He could have just said 'the NBER job does not pay enough'.

Reflections on blogging

Back
October 21st, 2007 by Walt

I was out of town for a couple of days. Regular posting should resume. (I was going to post beforehand to let you all know that I was going out of town, but then I thought “Who are you? My mom?”)

In Ars Mathematica.

Undercover Economist joins the blogosphere-proper

Tim Harford's practically-brand-new blog is here. I say blogosphere-proper because Tim is already prolific online, a de facto, if not de jure, blogger - check out his main site here.

You can order his books here; if you haven't read the Undercover Economist yet I strongly recommend you purchase a copy now (or I could lend you mine, as long as you promise to give it back).

Blogrush: dodgy math and lies

You may have spotted the little 'From the Blogosphere' widget that I recently put on the sidebar. The service is called Blogrush, and it has attracted a fair amount of attention in the blogosphere. Here's more, from their site(emphasis mine):

BlogRush is a "Cooperative Syndication Network." It's a network of blogs that run a small "widget" on their pages. Each time this widget is loaded it will contain 5 clickable headlines which are the blog post titles to other users' posts. Clicking on any of these links will open a new browser window and load the blog and full post. Users earn "syndication credits" based on each time their blog loads the widget as well as each time any of their referrals (users that signup after clicking the "add your blog posts" link on the widget) loads the widget. They also earn additional credit based on all the activity through 10 generations of referrals. 1 Syndication Credit = having one of their recent blog post titles served inside the widget on another member's blog.

Blogrush has been labelled a pyramid scheme by many in the blogosphere - and it is. This, in itself, is not a problem: if you are offered a deal and you accept it, it must make sense to you. Furthermore, there's no real money at stake, and you can choose to remove the widget from your site any time you please.

What I'm pissed off about is that they make an incredible commitment (that is, they lie) about the conversion rate from pageviews on your site to links to your site from widgets in other blogs. The total number of pageviews in the system (i.e. the number of 'syndication credits' of all members) will never be equal to the total number of pageviews times 5 (remember, each widget displays five links). In the absence of the referral system, the conversion rate from your own pageviews to links to your site should be 1 to 5. (the FAQ does not specify what happens with excess link spots: they post paid-for ads perhaps? The quoted piece refers to '5 clickable headlines which are the blog post titles to other users' posts') With the referral system, this conversion rate can only be higher and it is likely that it will go beyond 1 to 1 before long, so Blogrush will simply not be able to deliver on their commitments. Also, it is very unlikely that they are not aware of the math behind this: after all, they put bloody link allocation algorithm together.

To cut a long story short, I don't mind that blogrush is unlikely to be a good source of traffic (what most bloggers tend to complain about), but I am angry that they blatantly lie about the terms in the deal - which is probably illegal too.

Why bother posting on a bank holiday? Part 2

I now have the answer to this question, courtesy of the comments section and Tim Worstall, which is:

1) To reward loyal readers. A fair point and a regrettable part of the moral hazard that datacharmer accepted with his holiday cover, i.e. that we have far less incentive to cater for his loyal readers.

2) To create content for people that visit more infrequently but read older posts too. I'll begrudgingly accept this one, although I could have created the same amount of content for occasional visitors by posting 4 times on Tuesday and skipped posting for the 3-day weekend.

3) Because you might get a lot more visitors than you were expecting, possibly due to a link from another site.

On the subject of (3), I've revised my forecasting model to:
Visits = 119.8 - 33.2 * Weekend + 205.4 * TW, where Weekend is a dummy variable that takes the value of 1 for a weekend day and zero otherwise and TW is a dummy that takes the value of 1 if Tim Worstall links to this blog and zero otherwise, with all coefficients statistically significantly different from zero at the 95% level (and for the data miners amongst you, an R-squared of 44%).

Why bother posting on a bank holiday?

Site visits for bluematter show a very pronounced weekly cycle, with most visits at the start of the week (normally peaking on Mondays, including on this graph the 6th, 13th and 20th) followed by a decline down to least visits on Sundays:


Using the last 30 days data before today, Visits = 119.8 - 33.2 * Weekend, where Weekend is a dummy variable that is 1 for weekend days but zero otherwise. The coefficient on Weekend is statistically significantly different from zero at the 95% level.

Given that most of our readers are probably English and it's a bank holiday, I can expect materially less than 86.6 people to read this today.

On promiscuity, logical impossibilities, statistical ignorance and the blogosphere

This is Gina Kolata, writing in the NYT:

One survey, recently reported by the federal government, concluded that men had a median of seven female sex partners. Women had a median of four male sex partners. Another study, by British researchers, stated that men had 12.7 heterosexual partners in their lifetimes and women had 6.5.

But there is just one problem, mathematicians say. It is logically impossible for heterosexual men to have more partners on average than heterosexual women. Those survey results cannot be correct.

Notice that the federal survey refers to medians, so there really isn't any logical impossibility there. The British study, on the other hand, refers to means indeed - there can't be a median of reported sexual partners of 6.5 (unless it is an average of medians over a number of years or something equally weird). With means, assuming females define 'sexual partners' the same way as males, the study is based on a truly random sample and males don't travel abroad disproportionately more than females do, a logical impossibility indeed presents itself.

This is not to say that there is any excuse for the author reporting the federal survey and then going on to say that these numbers cannot be an accurate representation of reality. At the same time, the British study makes it clear that there is an issue with men on average over-reporting (or women under-reporting) the number of sexual partners they have, so the evidence supports the author's thesis (or in the case of the federal survey, it is not informative - but definitely not against. That is unless you make some simplyfying assumptions regarding the distribution and utilise the information from the British survey as a prior etc but let's not even go there).

What I found of real interest in all of this wasn't really Gina Kolata confusing means and medians - I can easily write 10 posts a day documenting abuse of statistics in the press. The really interesting bit is the blogosphere's reaction:

Crooked Timber, my original source, reports both results and goes on to quote Andrew Gelman: 'Jeff's response: MEDIANS??!! Indeed, there's no reason the two distributions should have the same median.' No mention of the fact the second result could not be referring to medians, and that it supports Gina Kolata's thesis.

The very, very, very clever Andrew Gelman discusses about the median, and then goes on to say 'Finally, it's amusing that the Brits report more sex partners than Americans, contrary to stereotypes.' As I mentioned above and a reader of Andrew's points out in the comments, the difference is between the American median and the British mean - not a terribly meaningful comparison to make. Andrew later acknowledged this in the comments - but I will have to put this down as the first time I have caught him off guard. I could bet good money he did not spend more than 10 seconds reading the article.

I'll lower that estimated time to 5 seconds for Ezra Klein, who even after attracting a flurry of comments pointing out that the results refer to the median rather than the mean (including from Robert Waldman ) defended himself by saying this:

My understanding has always been that these are mean numbers, as median numbers tend to specifically be reported that way. But this would be worth finding out.

To find out, of course, one would simply have to read the first three paragraphs of the original NYT article.

And last but by no means least, Brad De Long is taking the piss - but making sure he only quotes the irrelevant American results:

Ouch. Our own David Gale from the tenth floor is made to look ridiculous by Gina Kolata--you see, she didn't tell him that the survey didn't ask about means--about averages--but about medians. Which means that she doesn't know the difference between means and medians. Which is a very bad thing for a science reporter.

Brad spotted the second study, but he is reacting by deliberately posting the juicy bits only. Quoting the British results would not alter the conclusion that the NYT columnist really messed up here, so the issue is discreetly sweeped under the carpet (not that I find this an entirely wrong thing to do. I may be in a philosophical mood here, but there is an appeal to pithy and to-the-point posts on silly subjects such as this one).

By the way, my own first reaction was to admonish the use of the median in the NYT article - but after seeing the attention this was attracting from fellow bloggers I thought the post was worth expanding.

And as I think I should, here is Wikipedia on the mean and on the median.

The slave trade in paradise

This is an edited version of a fascinating post from an economist in paradise:

The history of Mauritius is inextricably linked to the slave trade. In 1806, the slave population reached 78 000, an estimated 85% of the population, for an island no more than 720 square miles.

Slaves changed masters via openbid ascending (English) auctions; males were sold separately, women and their children were sold as a bundle. Armed with a uniquely detailed data set gathered from notarial acts on auction sales over the period 1825-1835, economists Chenny, Dionne, StAmour and Vencatachellum ask two questions in two separate papers. Firstly, was the market for slaves in Mauritius characterised by imperfect information, whereby sellers (masters) had more information about the productivity of the slaves than potential buyers? Secondly, how did the British take-over of 1810 and rumours of abolition affect the market for slaves?

Between 1825 and 1835, 2827 slaves were bought and sold at an average price of 326 piastre per slave, that is around 320 US dollars (roughly a quarter of per capita US income of that time). The average price for a male slave was $337 and a female slave $288. There are three broad categories of slave occupation: ’skilled’, ‘labourer’ and ‘household’. Relative to the average male price, ’skilled’ males were sold at 15% more, ‘household’ males at 4% less and ‘labourer’ males at 7% less. Slaves that grew up in the island, called ‘Creoles’, were sold at at premium of 13% over the average slave price, those recently imported from Mozambique were sold at a 10% discount, those from Madagascar at a 3% premium and ‘Indian’ slaves were sold at a whopping 54% discount.

The question asked by the authors is whether these prices reflected fundamentals. In some way, they do: ‘Indian’ slaves were ’smaller’ people and perceived to be less productive than their ‘African’ counterparts, while the ‘Creoles’ were perceived to be more adapted to local conditions. But the authors also find that asymmetric information was prevalent in the market for slaves: the circumstances under which a slave was sold dictate his/her price.

There are, in fact, three reasons for a slave to be sold: (1) death of the owner, which under Mauritian Law, required the assets of the deceased to be sold off and the proceeds distributed to the heirs, (2) bankruptcy of the owner and (3) voluntary sales. Two main findings emerge. Firstly, when male slaves are being sold involuntarily (death or bankruptcy of the owner), they were traded at a big premium (around 45% above the price of a slave sold voluntarily). Secondly, if, when a slave was being sold involuntarily, a relative of the owner participated and won the auction, the slave is generally traded at an even higher premium. This seems logical since relatives had insider information about the slave and would only bid aggressively when the slave is known to be productive.

Rumours about abolition

In their second study, the authors attempt to deduce whether slave owners believed in the persistent rumours that the British would abolish slavery. One way of finding this is to assess the market for children slave. Since children slave would only be productive in the future, rumours about abolition ought to depress their prices. In fact, they observe that the price for children slave rose between 1825 and 1827, from which they conclude that slave owners did not treat abolition as a serious possibility. Indeed, the threat only started to reveal itself in the data after 1833, two years before actual abolition.

Technological change

Improvements in technology took the form of the introduction of the horizontal roller mill in 1819, and steam-driven rollers in 1822. It seemed that technology ironed out differences in productivity as the price discount on handicapped, Indians and Mozambicans fell in the slave market.

The slavery period was undoubtedly the grimmest part of Mauritian history, the consequences of which are still being felt, more than five generations later. Descendants of slaves, who account for quarter of the population attain, on many counts, much less than the average Mauritian. Is there, after terrible uprooting, a degree of path dependency that we economists tend to seriously underestimate?

The papers are here and here. By the way, An Economist in Paradise provides an invaluable 'live-at-the-scene' perspective into Mauritius and the economics of developing countries in general, and is well worth a place in your bookmarks folder.

Supranational law revisited: A reply to Tim and Dave

There were a couple of interesting points raised in response to a previous post on supranational law. Here is Tim Worstall:

The German Constitutional Court (whatever it's called) has, I think, stated that where EU law calls for a breach of the German constitutional law, then it is the EU law that must be changed, not the German constitution.

On the basis that EU law is imposed by treaty, whereas the constitution is more basic than that perhaps?

Or another way of looking at it, that a treaty cannot be used to impose a breach of constitutional law: very much the problem over the Extradition Act with the US. Americans' cannot be extradited to the UK on the same basis that UKites can be to the US because the US courts take the view that said treaty violates basic constitutional protections and therefore cannot be used in the US.

I'm well aware that EU law does over ride domestic law and the question I was trying to raise is, will a UK Constitution lead to something like the German or US situation?

Any UK constitution, if there ever is one, will take its rightful place above UK law and below EU law and other international treaties the UK has signed. The German constitution is no different: Germany may try and argue against instituting a certain piece of EU legislation that goes against the German constitution or, if that's not possible, it may choose to ignore that specific piece of legislation and face the consequences of breaking EU law. There are many examples of EU countries consistently refusing to enforce certain pieces of EU legislation, and they duly pay the resulting fines as specified by the EU. An individual may choose to pay parking fines rather than use public transport, but this does not mean he is above parking law.

As for the UK-US Extradition treaty, keep in mind that it was only recently ratified by the US, while the UK unilaterally chose to enforce it earlier than the Americans did. At any rate, my understanding is that the US is not flouting the treaty: it just made sure that the requirements imposed on it were in line with its constitution. If it were indeed the case that its constitution did not allow it to enforce the treaty, it would be the UK's right to refuse to honour its part of the deal too, and the treaty would no longer have any legal force.

Approaching the issue from a different angle, Dave also makes an interesting remark:

Surely no EU law is actually law in the proper sense because there is no means of enforcement, given the sovereignty of nations. Therefore, when we talk about EU law, it is in rather optimistic terms (just as we do about the UN). Surely national law precedes international treatises, just as natural law precedes national.

The EU has a variety of means of enforcement, ranging from fines to expulsion from the union itself. Of course, at any point in time any country can choose to renege on a treaty/law, but then it would have to face the consequences, whatever these are. This is also the case for lower-level authorities or individuals who may choose to break national law. From a moral point of view, you may be right: any entity can flout a law it is subject to following its own morality or, in the case of countries, legal system. But from a legal perspective, my point still stands: it is absolutely impossible for a lower-level entity to legislate in contradiction to a higher-level law.

One more quick point is in order before leaving this post. While it may seem that I am eager to pick on Tim Worstall, I have to make clear his blog is great, and I am one of his most loyal readers. I don't always agree with everything he says, but in most cases he has a good point - and a unique way of expressing it. Furthermore, his ability to maintain a high level of quality while being probably the most prolific econ-blogger around never ceases to amaze me. Tim, keep up the good work - and I will keep trying to get to the bottom of your arguments.

Best econ blogs

This is for 2005, via Newmark's Door. An excellent idea, and a classy execution.

I'll have a crack at producing my own for 2007 soon, so stay tuned.