Archive for the ‘economia’ Category

Externalidades, Reação a incentivos e outras questões

janeiro 23, 2008

A privatização de rodovias é uma questão interessante de ser analisada. Uma das regras básicas da economia é que as pessoas reagem a incentivos. Quando se privatiza uma rodovia, os motoristas tendem a reagir ao pagamento de pedágio através da busca de uma alternativa disponível grátis. Como estas alternativas são de estradas em condições físicas ruins, a conseqüência não prevista (ou seja, externalidade) da privatização é a possibilidade de um aumento nas mortes no trânsito nas outras rodovias. Uma alternativa seria a cobrança para todas as rodovias; em outras palavras, privatizar tudo. Através de aparelhos GPS a cobrança seria relativamente fácil. Esta cobrança seria muito mais justa do que a situação atual, onde mesmo quem não usa as rodovias paga por sua manutenção.

Anúncios

Economia Brasileira

janeiro 18, 2008

A seguir, uma análise da economia brasileira pela The Economist

This time it will all be different
Jan 17th 2008 | SÃO PAULO
From The Economist print edition
Why Brazil is better placed than it used to be to cope with a world slowdown

BRAZILIANS know about economic and financial crises. The squalls afflicting America and threatening Europe look like a gentle breeze when compared with the frequent and violent blow-ups that litter Brazil’s economic history. Much of the problem has been Brazil’s vulnerability to shocks imported from around the rest of the globe. So what might happen if the economies in the rich world stumble again this year?
Recent precedents do not look good. Since the introduction of a new currency, the real, in 1994, which serves as the year zero for economic policy, growth has picked up to a reasonable rate three times. Each time, points out Eduardo Giannetti da Fonseca, an economist, people have speculated that Brazil was at last on the road to a bright new future. And each time something has come along to puncture this optimism: in 1998 it was the Asian financial crisis, in 2001 Argentina’s bond default and in 2005 a rapid rise in inflation.
Now bullishness is abundant once again. The economy grew at an estimated annualised rate of 6% in the final quarter of last year (which is probably too fast). The Bovespa, Brazil’s stockmarket, jumped by 60% in value during 2007. And yet even though recent history counsels caution, there are reasons to believe that the economy should cope better with whatever the world throws at it.
“Brazil has never been so well placed to face a downturn,” says Mailson da Nobrega, finance minister from 1988 to 1990, a period that coincided with an inflation crisis. He now works for Tendencias, a consultancy. Arminio Fraga, who was in charge of the central bank during the Argentine collapse and the bond market’s swoon at the prospect of Luiz Inácio Lula da Silva’s election as president, cautiously agrees. “A lot has been driven by favourable winds,” says Mr Fraga, who now runs Gavea, an investment fund. “If they stop then we are not in a position to blow up, but it won’t be irrelevant.”
What changed? First, domestic demand is strong. Brazil’s headline real interest rate is just below 7% which, as Alexandre Bassoli of HSBC bank points out, would tip most countries into recession, but is low by Brazilian standards. The result has been a flowering of credit, which helped domestic demand grow by an annualised rate of almost 7% in the third quarter. It would take a sharp rise in rates to kill this off, and that looks unlikely.
Second, Brazil is fairly well integrated into world markets. It is not overly dependent on America, which accounts for less than a fifth of exports. The remaining four-fifths are reasonably well spread between Europe, Asia and the rest of Latin America. Admittedly, most of what Brazil produces for foreign consumption is in the form of primary goods (from orange juice to footballers), which means that export growth correlates strongly with commodity prices. But exports are not made up of any single commodity (unlike oil-rich Venezuela’s, for example). “Even if China buys less Brazilian iron ore, the hope is that Chinese people will keep eating Brazilian protein,” says Jose Mendonca de Barros of MB Associados, a consultancy.
Third, Brazil is less vulnerable to financial shocks than it once was. A large part of this is due to a combination of a central bank that acts independently and transparently, publishing minutes of meetings promptly on its website; and a floating exchange rate, adopted in 1999. Before then, whenever the current account deteriorated, the central bank was forced to hike rates, killing growth.

Brazil has retired its dollar-denominated debt, which has been a source of trouble in earlier financial crises. In the past, when the currency depreciated this debt ballooned, causing further problems. Now that government debt is denominated in reais, a similar move in the exchange rate reduces government liabilities. This was tested in August last year, when the real lost 11% of its value in a couple of weeks, and the government debt effectively shrank. Foreign direct investment is strong, and Brazil now holds more dollars than it owes, a happy development that has led to misguided suggestions of setting up a sovereign wealth fund.
Even so, Brazil is clearly far from immune to what happens in the rest of the world. The economy also seems to be moving into a less benign phase. After years of big surpluses, the current account looks set to run a small deficit this year. Inflation, which had been falling, picked up toward the end of last year to give an annual inflation rate in December of 4.5%. That is right on the central bank’s target, and forecasters expect inflation to increase only slightly this year. But markets have been wrong on this before.
Moreover, the economy still suffers from problems that make growth above 5% look like a stretch. Government debt is still too high, Brazil invests too little, and the government takes too much for itself, spending it on things that do little to raise the economy’s potential. “The easy part of growth is over,” says Mr da Fonseca. But if Brazil is able to sustain steady growth without being blown off-course by events elsewhere, the country will look very different in ten years’ time.

Economia e Sexo

janeiro 18, 2008

Segundo a The Economist (Selling sex, 17/01/2008), o encontro da American Economic Association deste ano foi dominado por uma sessão onde de discutiu o mercado de sexo pago (prostituição).

O trabalho foi desenvolvido por Steven Levitt, co-autor de “Freakonomics”, e Sudhir Venkatesh. Eles pesquisaram as transações de prostitutas nas ruas de Chicago.
Os resultados:
=> A indústria está concentrada em termos de locais pelo fato das prostitutas e seus clientes necessitarem de um “ponto de encontro”
=> O lucro é alto, quando comparado com outros trabalhos (de 25 a 30 dólares por hora, ou quatro vezes o salário normal)
=> Risco é elevado pois o sexo sem proteção é algo normal.
=> A chance de assalto é elevada (média de uma vez por mês)
=> O risco de problemas legais é baixo (a chance de serem presas é menor que terem sexo com policiais)
=> Estratégia de preço é igual a outros tipos de negócios. Os preços são segmentados e o valor varia conforme a percepção da habilidade de pagamento do cliente
=> O mercado absorve um aumento de demanda (através de um evento nas proximidades de um ponto) por conta da flexibilidade de oferta.

Recessão

janeiro 16, 2008

Esta é uma maneira interessante de verificar a possibilidade de uma recessão no futuro. Conta-se o número de vezes que a imprensa (New York Times e Washington Post) usou a palavra “recessão” nos textos. Pelo gráfico, publicado na The Economist, autora do índice, teremos uma recessão nos próximos meses.

Links

janeiro 10, 2008

1. Os melhores e piores comerciais de 2007 nos Estados Unidos e aqui em português
2. Cinco marcas famosas que ajudaram Hitler
3. Carreiras de futuro (e não tem o contador)
4. Abordagem econômica para os problemas diários

O vínculo entre economia e guerra

janeiro 9, 2008

Desde o fim da segunda guerra mundial, o mundo já conviveu com mais de uma centena de guerra civis. O resultado destes conflitos foi mais de 16 milhões de vidas. Uma possível explicação para a existência deste tipo de conflito é a economia. Os países menos desenvolvidos geralmente dependem de poucos produtos para obter divisas. Quando o preço destes produtos reduz no mercado mundial, a chance de um conflito é maior. Markus Brückner e Antonio Ciccone (aqui) analisaram esta questão e encontraram alguns vínculos. No período entre 1997 e 2000 o preço internacional do café caiu em 50%. Três países da África que dependem da exportação do produto, Burundi, Ruanda e Uganda, iniciaram uma guerra logo após (em 2000, 2001 e 2002, nesta ordem).

Pesquisas econômicas do ano

dezembro 27, 2007

Neste endereço uma seleção de pesquisas econômicas do ano. Algumas delas citamos aqui neste blog. Outras parecem interessantes, como é o caso da pesquisa de Justin Wolfers sobre a discriminação racial dos árbitros da NBA ou as pesquisa de David Galenson sobre arte (a sobre a evolução da música no século 20 é realmente interessante)

Várias delas encontram-se no sítio do NBER, o que é mais um indício da importância de consultar este endereço.

Para a contabilidade, destaco o texto que mostro que a Sarbox não fez Nova Iorque menos competitiva, o texto sobre propriedade intelectual e mágica (mostrando os segredos da ausência de propriedade intelectual no setor) e a relação entre desempenho da empresa e a mansão do seu presidente.

Previsão na Economia

novembro 25, 2007

Um análise do livro “Imperfect Knowledge Economics”, de Roman Frydman e Michael Goldberg, feita pela The Economist, mostra dificuldade de fazer previsão em economia. Para Frydman, aquele que faz previsão usa métodos quantitativos, mas também a intuição e o julgamento. “Ele não é um cientista”, afirma Frydman, e este fato tem sido ignorado pelos economistas, que perseguem a previsão perfeita, apesar de toda prova em contrário de que ela não existe. Frydman e Goldberg destacam o desempenho das agências de ratings no mercado de títulos versus o CDO. O desempenho no primeiro é melhor pois se usa um modelo matemático em conjunto com o julgamento de especialista, enquanto o segundo só trabalha com modelo quantitativo. A reportagem encontra-se a seguir:

A new fashion in modelling
Nov 22nd 2007 – From The Economist print edition
What to do when you don’t know everything

“THE forecaster is like an entrepreneur,” says Roman Frydman. “He uses quantitative methods, but he also studies history, and relies on intuition and judgment. He is not a scientist.” According to the New York University economist, this fact has been lost on contemporary economists, who continue to pursue the perfect economic forecast despite abundant evidence that it does not, and cannot, exist. They dismiss their repeated failures in much the same way that self-styled reformers in Mr Frydman’s native Poland once insisted that socialism was great, but just needed to be carried out better.

In the economics profession the leading inheritors of this communistic mindset, says Mr Frydman, are the proponents of rational-expectations theory, which assumes that the economy and the individuals within it act with perfect foresight. Yet he is equally critical of the more fashionable school of behavioural economics, or at least those of its practitioners who claim that although people are irrational, their irrationality can be modelled so precisely that the future can be forecast with great precision.

In a new book, “Imperfect Knowledge Economics”, written with Michael Goldberg of the University of New Hampshire, Mr Frydman sets out an alternative approach to prediction, in which the forecaster recognises that his model will inevitably be less than perfect. Their work has received glowing praise from Nobel-prize-winning economists such as Kenneth Arrow and Edmund Phelps, who wrote the introduction to the book—though it is unlikely to have gone down so well with Robert Lucas, who won the Nobel for his work on rational expectations.

There is nothing new in economics about the idea that people must make decisions based on imperfect knowledge. Frank Knight gave his name to “Knightian uncertainty” thanks to his 1921 book, “Risk, Uncertainty and Profit”, which noted that most business decisions involve a step into an unknown that is to some degree unmeasurable. And John Maynard Keynes observed that “human decisions affecting the future, whether personal or political or economic, cannot depend on strict mathematical expectation, since the basis for making such calculations does not exist.”

While reflecting these insights, imperfect-knowledge economics still sees a role for economic theory in forecasting. Messrs Frydman and Goldberg argue that, to be useful, economic forecasting models should be based on qualitative regularities in the way that market participants respond to new information—that is, patterns of behaviour that are observable and somewhat predictable. Though not perfect, these will often give a better clue to the future than no model at all, or models based on rational expectations or behavioural economics.

Take bulls and bears, for example. Their analysis of the fundamentals leads them to opposite conclusions about where prices are going. But there is evidence that the way they revise their forecasts in the light of price movements may share common features, such as a tendency to become more risk averse the further the price of an asset moves away from what is generally believed to be its long-term fundamental value. This may work eventually to return the asset price to its fundamental value, though it may also cause it to deviate significantly from this value for long periods of time. This approach will not generate the “sharp predictions” beloved of most contemporary economists—which are doomed by imperfect knowledge to be wrong. But it will provide a broad sense of the state of play, which an enterprising forecaster can usefully combine with experience, intuition and so forth when making a decision.

To show how this works, Messrs Frydman and Goldberg examine the persistent failure of economists to predict movements in the currency markets. According to Kenneth Rogoff, an economist at Harvard who has long attempted to find rational models for predicting currency fluctuations, “it is stunning how hard it is to explain movements in exchange rates.” All the models based on rational expectations now say that, on fundamentals, the euro is overvalued against the dollar, he reckons. But does that mean the dollar will soon rise? Mr Rogoff says he has no idea.

In rational-expectations theory, a range of variables including inflation, interest rates and growth should have a predictable impact on currency movements, but in practice this theory has proved less useful for forecasting than tossing a coin. Among rational economists, the debate is over “whether the glass is 5% full or 95% empty,” he says. Only over longer periods—say two to four years—is there any evidence of exchange-rate predictability, which is far too long to be useful to traders or policymakers.

By contrast, the model developed by Messrs Frydman and Goldman, which assumes imperfect knowledge and learning, does significantly better than tossing a coin, although it is by no means right all the time. Mr Rogoff describes this work as innovative. Now, however, it must demonstrate that it can consistently maintain explanatory power in the future and over a range of markets, he believes.
Maths lesson

Messrs Frydman and Goldberg are now turning their attention to the troubled subprime-mortgage markets, and the performance of the rating agencies. The rating agencies, argues Mr Frydman, have generally been better at rating corporate bonds than rating asset-backed collateralised-debt obligations. Why? One reason is that the rating agencies used both a mathematical model and the judgment of their in-house specialists when forecasting the default probabilities of corporate bonds; on subprime-related securities, they could only use mathematical models, not least because the instruments were so new. “They had no experience, no intuition, no entrepreneur,” he says. That is “empirical proof that relying on models alone is not wise.”

Links

novembro 21, 2007

1. O que significa I Love You para um economista

2. Legibilidade nos livros. Os livros de sucesso são mais fáceis de serem lidos.

3. Um estudo sobre os benefícios econômicos da possibilidade de liberação do casamento gay em Nova Iorque

Qual o limite da economia (ou dos economistas)?

outubro 29, 2007

Tim Harford é um economista conhecido pela sua abordagem não tradicional, comentando sobre café e outros temas curiosos. É uma versão inglesa do Freakonomics.

Mas o limite para os comentários de Harford não são amplos demais? Aqui Harford responde a uma leitora sobre virgindade. Aqui compara o valor da vida. E aqui discute a questão da pontualidade.