Are wars rational?

There are few circumstances where wars are globally welfare enhancing. One can imagine that wars can be individually optimizing, for example when we consider the old land-taking or enslaving war. But casual empiricism indicates that quite often fools engage in wars, like minnows tickling obviously overpowering giants (Irak, North Korea) or others who have little objective chance of winning (South Ossetia, Caprivi, Falklands). Is it because some belligerent are poorly informed or even irrational?

Clara Ponsati and Santiago Sanchez-Pages use Markov games with fully rational players to characterize wars, and even chronic wars. A country can lay a claim on another country, leading to bargaining or war, and it can only end if one surrenders. The problem is that parties do not know their relative strengths and can only learn about them by engaging in war. Add a dose of optimism, and you have a recipe for war. Were one to add some political economy (or populism) to this model, outcomes would be really depressing and worrisome. But I still have some faith in humanity.

Interest-only mortgages and house price bubbles

Bubbles are annoying. First because they are difficult to identify, second because they indicate that prices do not reveal the "proper" information, and third because they lead to misallocation of real resources and much hardship when they burst, which they inevitably do. You want to prevent bubbles from happening, but again they are really difficult to identify, especially in real time.

Gady Barlevy and Jonas Fisher may have figured out a clever way of identifying bubbles in house prices. Using some theory, they find that interest-only mortgages should only be used if there is a bubble. Turning to data, they find that the use of such mortgages is rather sparse through time and space, and when it is used, it corresponds pretty closely to episodes where we suspect bubbles could be happening. In particular, interest-only mortgages mere mostly used in areas with inelastic housing supply, which are more prone to bubbles.

Is there really no selection bias in laboratory experiments?

Whenever you read about a survey or an experiment, the first worry one should have is whether there is some selection bias in the studied example. As I have argued before, experimental economics is almost exclusively on a sample from a minority of the world population. But assuming that we are only interested in this minority (and unfortunately we are), is there still some selection bias.

Blair Cleave, Nikos Nikiforakis and Robert Slonim did some experiments in the classroom with over 1000 students, and then invited them for more experiments in a laboratory setting. Those that followed the experiment did not have different characteristics, which is reassuring. However, this only partially alleviates my worries. Indeed, students are only a small minority of the current population, one that is more educated, coming from a richer background, younger, etc. I am looking forward to a broader study...

Time for an agricultural revolution in Africa?

When you think about income differences across the world, Africa is really depressing. It seems nothing is making a lasting impact in terms of policy for it to catch up with the others, and seeing how Asia managed to transform itself makes you wonder what is fundamentally wrong. While one may think this has to do with misguided policies, so much has been tried that something ought to have stuck. But no. One thing that helped Asia is that evolution in rice brought an agricultural revolution that freed human resources for manufacturing, so could such a revolution also happen in Africa?

Donald Larson, Keijiro Otsuka, Kei Kajisa, Jonna Estudillo and Aliou Diagne claim that several areas in Africa are suitable for rice, but local diets and tastes are too diverse for rice to have the success it had in Asia. The productivity of other crops needs to improve as well. So it does not look like there is a ready-made solution that will kick-start the agricultural revolution soon, despite some very localized successes.

That said, why insist of improving agriculture on a continent that is visibly not appropriate for this? Much like telecommunications in Africa jumped over landlines directly to mobile telephony, why not bypass agricultural development straight to manufacturing? One argument against this is the large transportation costs that make local agriculture essential and manufacturing away from the ports unprofitable. But why insist on keeping the population on the countryside? Why not develop coastal cities and take advantage from returns to scale there, like Singapore and Hong Kong did, and

An analysis of the oldest auction in history

Homo economicus is not a recent phenomenon. Not only that, he design market mechanisms early in history that appear to be very subtle. The oldest known auction was designed by Illyria in Babylonic times. This is a marriage markets in its true sense, as it is about auctioning off potential brides. All eligible girls are assembled, and an auctioneer offers them to the highest bidders, starting with the one expected to fetch the highest price. Proceeds are used to sell the least attractive brides to the poorest men assembled.

Michael Baye, Dan Kovenock and Casper de Vries analysis this auction in a two-player environment and claim that there is something paradoxical. Assume complete information, which means the auctioneer will always earn zero profit. Then is appears players can earn a much larger surplus by playing a mixed strategy than with a pure strategy. And there a continuum of these mixed strategies, and the expected payoff for both players is arbitrarily high, but finite. The problem is the solution procedure used to solve for symmetric mixed strategies breaks down here, because it selects strategies that are not part of Nash equilibria. We should learn from that to be very careful when applying standard theorems. A similar reasoning applies to incomplete information where the bidders do not know how much the other player values the potential brides.

There is no recent literature on this auction. However, it was mentioned on the back cover of the August 2006 issue of the Journal of Political Economy. I suspect this is what inspired the authors to work on this. They could have mentioned this and acknowledged the submitter, Costas Meghir.

Markets under-value fuel economy for new cars

Is it worth it to buy a fuel efficient car? If you ask an economist, he will look at the fuel consumption, the cost of gasoline, and calculate the cost benefit of a fuel efficient car, probably also factoring in a resale value and a discount rate. But a non-economist customer?

David Greene says the literature is really unclear, as customers seem to be under-valuing and over-valuing fuel efficiency depending on how you look at the data. Surveys seem to indicate that car buyers consider a very short horizon for the payback, 1.5 to 2.5 years. That makes it very difficult for fuel efficient cars, hence the need for subsidies, or better taxes on the inefficient cars (see why). But this provides little theoretical insight where car buyers differ from the economist I described above. Greene thinks this has to do with risk aversion about future gasoline prices, or loss aversion (being afraid of having taken a poor decision). But clearly, this requires more research.

Having said this, I am puzzled at how little hybrid cars have been adopted in Europe, in particular compared to the United States. The cost of European gasoline is very significantly higher, and the environmental consciousness is also more pronounced. Is it because the alternatives to hybrid cars, the small fuel efficient sedans, are much better than in the US?

Are payday loans any good?

Payday loans are small loans that are offered with very short terms, usually until the next payday. But because they imply exorbitant interest rates, into the hundreds of oercent in annualized rates, they are severely criticized. Yes, the payday loan industry is thriving, obviously responding to a strong demand. So it would appear that payday loans are welfare improving, or people would not use them, just as much as credit card loans are welfare improving. But many people worry that payday loans, more so than credit card loans, lead borrowers into a vicious cycle of financial dependence. So, should they be regulated out of existence or not?

John Caskey writes that the issue is really about separating two kinds of people. There are first those who fully understand the terms and the cost of the loan, but happen to face a very short term liquidity crisis, having exhausted or having no access to other forms of credit. This can happen to the best people, and happened to me. For them, the payday loan is valuable and clearly welfare enhancing as it fills some market incompleteness. And there are other people who are tempted by the easy cash and immediately face long term issues in paying the loan back. The policy maker would want to prevent the second category to get such loans, but one may ask whether the payday loan industry would want to grant them business as well: they are clearly much riskier. The loaner would want to find a way to discriminate, in particular because this allows to reduce the interest rate on the good borrowers and thus attract more of their business.

But the data indicates the second category is worryingly big. Only one sixth of payday customers borrow once a year or less. And it is estimated 5% of the population would use those loans if they were freely available in every US state, like it is currently the case in some. That would be worrisome. But when Oregon regulated the payday loan industry away, people felt more constrained. And states with payday loans have significantly fewer checks bouncing, although they also have more bankruptcy filings. The paper offers plenty of other examples from the empirical literature, but overall, there is no clear sense whether payday loans are welfare improving or not. Maybe better discrimination of customers is the way to go.

Another year of blogging

How quickly that year passed, and I am once more amazed at the quantity I have posted. One hardly notices when you write a couple of paragraphs each day, but it sure accumulates: 271 posts during the year, 40 more than the previous year, reflecting the lack of vacation time...

Should I continue? I still like doing it, even though it takes much more time to write even two paragraphs about a paper than simply reading it. While I do not have credible statistics to back it up, I have the impression that I have a rather loyal (and mostly silent) readership. There are over 700 subscribers on the Google Reader I use, probably more elsewhere and through various relays. I only wish there were more discussions, although I understand it can be difficult to participate.

Comments averaged at two a post, a rather modest number. But some posts attracted a lively discussion. Here are the ones with the most comments:

1. Why criticize modern macro when you do not follow modern macro?
   
2. The economics of compartments
   
3. On the dangers of penny auctions, an example
   
4. Is democracy really worth it?
   
5. About this obsession with lawns
   
6. Doing Calvo all wrong
   
7. About the state of US higher education
   
8. Smoking bans versus tobacco taxation

And which were the most popular posts of the year?

1. The economics of compartments
   
2. Worker overconfidence and unemployment duration
   
3. What is an MBA worth? (from 2008!)
   
4. How to increase employment, and at what cost (from 2009)
   
5. On the dangers of penny auctions, an example
   
6. Is the US a third world country?
   
7. Posting calories in restaurants is Pareto improving
   
8. The AEA is missing a golden opportunity
   
9. The problem with experimental economics: people are weird
   
10. Household size heterogeneity and the representative agent

Anyway, here come another year of blogging on research in Economics.

The impact of poor climate

We often cannot choose where we live, especially as academics, and have to bite the bullet when we end up in places where the climate is less than favorable. You sometimes wonder why humans willingly decided to settle in numbers in uninviting places. And it matters, as people not like poor climate, but that may be compensate by other factors, like having a job. Still, climate matters for satisfaction.

David Maddison and Katrin Rehdanz document using the world values survey that poor climate has a significant impact on life satisfaction. The latter is defined by self-reported survey results, thus to be taken with a rock of salt, and poor climate is defined by a measure akin to a standard deviation from a comfortable temperature, 65F or 18C. How significant the impact is cannot be evaluated without seeing some statistics about the climate measure, but let us believe the authors for a moment. This means that, ceteribus paribus, people in Central America and some parts of Africa should be the happiest. Of course, all other things are not equal. And there may be others things that correlate with temperature variations that also have an impact of happiness. For example, long nights in the winter have a strong impact on depressions in Nordic countries.

Maddison and Rehdanz then proceed to look at the consequences of a climate change scenario which provides country specific temperature changes. From this exercise, they find that Europe will gain in satisfaction, the US will be unaffected and Africa will suffer tremendously. While this is an interesting first shot at the question, I am not quite sure I am willing to run with it. In particular because the initial elasticities may be tainted by correlates that do not vary with climate change (for example, length of night is not expect to change), and because climate change will have other important consequences, for example about the availability of fresh water. But at least, this paper gets us thinking about these issues, and it highlights that those who would suffer the most are those that have the least to do with the origin of climate change.

How to fight tax evasion

Tax evasion is a serious problem in developing countries because of the tiny administrative capacity of authorities and the size of the informal sector. Even in more developed economies, say, the Southern European ones, tax evasion is part of daily life. Again, administrative capacity is lacking. One could even argue it is a problem in the United States seeing the tiny auditing staff of tax authorities and the complexity of the tax code. Tax auditors have thus to define priorities.

Mirco Tonin studies the rules that Italy and Bulgaria instituted. In Italy, businesses and self-employed people reporting revenues below some level are subject to higher scrutiny. The idea is thus not to go after those who declare to be big fish, but rather those who may hide it. And making it known that there is such a threshold induces people to declare more to tax authorities. In Bulgaria, authorities are after employees and firms that declare too little in social security contributions. This is also forcing them to declare more to avoid scrutiny.

Tonin uses a model of imperfect monitoring to figure out whether such threshold rules make sense. And yes, they improve tax revenue, as those who have higher true income declare more than the threshold, and those below become more truthful. Now all you need to do is figure out where to put the threshold to equalize marginal tax revenue and marginal auditing cost, possibly adjusted by the dead-weight cost of taxation and for observable characteristics of the tax payer.

Are consumption taxes more equitable?

There is no doubt that consumption taxes are more efficient that labor income or capital income taxes, because they do not punish activities one would like to see promoted in an economy (labor supply, investment). But they are widely regarded as unfair, as the consumption share of income is higher for poor people. Hence the implementation of exclusions for essential goods where consumption taxes exist, in order the achieve some tax progressivity.

Isabel Correia claims that switching from income taxes to consumption tax can lead to less inequality even in the absence of lump sum transfers. This is a very counterintuitive result, and this is probably the reason why it made it into the American Economic Review (Yes, I know, I am breaking a trend here). But despite my best efforts, I still do not understand how this could happens, and the article provides very little in terms of explanation. Not only is no intuition provided, but the idea of using Gorman aggregation to reduce the model to a representative agent model seems wrong in this context. If anybody has read and understood the article, please help me here.

How not to encourage home ownership

Many governments try to encourage home ownerships by various means. I am not convinced this needs encouraging, as it leads to over-acucmulation of residential capital. Additionally, it is a myth that home ownners are happier and better citizens, as I reported previously. But suppose, for a moment, that a government really wants to increase the home ownership rate. How could this be best achieved. Two recent papers look at this.

First, Emre Ergungor compares mortgage interest subsidies to mortgage down-payment subsidies, and finds the latter work better. It is clear that down-payments are a significant hurdle for first time home buyers, and the recent crisis has at least partly been attributed to too easy down-payments, so one needs to be careful with this result. This is why Ergungor looks at loan performance for low to middle incomes. He finds that a one percent interest reduction is equivalent to a $3200 down-payment subsidy in that it leads to a 75 point reduction in default rates, and the latter is much cheaper to implement.

Second, Christian Hilber and Tracy Turner make the point that the tax deduction of mortgage interest makes mortgages more affordable but also raises house values. So in the end who benefits? Apparently only higher incomes in markets with few regulations. Hilber and Turner do not try to explain why this would happen, but I suppose this has to do with the high marginal rates on tax expenditures for high incomes, although I cannot explain the regulatory impact. In any case, there is more evidence that this type of subsidy should be abandoned.

ABM+NKDSGE=?

Agent-based models have a track record of generating stock market bubbles when they include agents that are not optimizing and use backward-looking decision rules. But they do not seem to have convinced the profession of their relevance because of the perceived arbitrariness of model components and the fact that they basically predict that a broken clock is right twice a day. Hence, it should be quite interesting to try to embed an agent-based model into a more widely accepted model and see how far this can bring us.

Matthias Lengnik and Hans-Werner Wohltmann do this by including two type of asset traders in a Neo-Keynesian model: fundamentalists, who are forward-looking and expect that price will get closer to the fundamental equilibrium, and chartists, who are backward-looking and obey some predefined rules based on past prices. This introduces some degree of history dependence and assumes that both types of agents are fooled every time. They never learn. And asset prices are thus essentially exogenously determined. The non-financial part of the model follows some old-fashioned model where inflation linearly impacts the output gap, and inflation is determined by the output gap and the evolution of stock prices. In other words, we are back the wind-generating hand-waving of 1980's macro, and not exactly something I would call DSGE.

Anyways, let's see what comes out of this. Of course, by the very nature of the model, there can be multiple equilibria, and an unstable equilibrium is possible. So one has to be very careful with simulations as potentially a lot of scenarios are possible. Yet, Lengnik and Wohltmann base their entire analysis on a single 40 quarter run of their model. They call is "representative." In which sense? Have all runs the same statistical properties? Or did the authors mine for the most convenient one? None of the results can be believed until this is clarified.

Suicide in happy places

It is quite baffling that the countries with the highest standards of living, and among several dimensions the happiest ones, also exhibit the highest suicide rates. Is it that places where material necessities are easily met other more psychological worries take over? Is it that somehow happiness is more volatile, or more diverse?

Mary Daly, Andrew Oswald, Daniel Wilson and Stephen Wu use two data sets that allow to compare suicide rates and happiness across US states to show that this paradox is also true within the United States. This thus invalidates the cultural or institutional explanations of the international paradox. This also allows to use all sorts of cross-state controls, but none makes the paradox disappear. Daly, Oswald, Wilson and Wu then conclude that there must be a direct causality from happiness to suicide: living among happy people is depressing for some. This may be consistent with the fact that suicide rates drop in war time. And it is difficult to imagine the reverse causality, that high suicide rates make survivors happy.

The economics of swinging

This is not about economic fluctuations or long cycles like Kondratieff cycles, this is about the sexual practice of partner exchanges or group sex. This practice that started in US military families in World War II has now spread world-wide, first as wife swapping than with women's emancipation into couple exchanges that a organized through websites or swinging clubs. Estimates vary widely, but somewhere between 1 and 15% of the population practices it.

Fabio d'Orlando tries to explore the economics of swinging. In the absence of much data and theory about it, he draws heavily on Jeremy Greenwood and Nezih Guner's theory of the emergence of premarital sex (discussed here) and modifies it to a theory of increasing kinkiness of sex. I did not think this was very inspiring in this paper, but a (long) footnote caught my eye.

Swinging clubs charge an entrance fee, which depends on who enters. Couples pay, say, $50, but single men $150. This is more than a night with a prostitute, but single men seem to value of having sex with a woman who does not fake it. Single women, however, are typically not allowed in on the premise that they are prostitutes. The interesting bit is how a swinging club owner should maximize profits, given that couples are more likely to come if there are fewer single men. Given the hidden nature of this market and thus the lack of information, it would interesting to see the diversity of outcomes.