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Showing posts with label ratio. Show all posts
Showing posts with label ratio. Show all posts

Sunday, 10 September 2023

A level Economics: How Chicago school economists reshaped American justice

From The Economist

In recent years the antitrust division of America’s Department of Justice has gone on a crusade against corporate mergers, filing a record number of complaints in an attempt to stop the biggest businesses from getting even bigger. With few exceptions, these efforts have been thwarted by the courts. That it is so hard to get a judge to intervene in business reflects the work of an institution known more for its free-market influence on economics than the law: the University of Chicago.

Fifty years ago this autumn Richard Posner, a federal judge and Chicago scholar, published his “Economic Analysis of Law”. Now in its 9th edition, the book set off an avalanche of ideas from Chicago school economists, including Gary Becker, Ronald Coase and Milton Friedman, which passed into the folios of America’s judges and lawyers. The “law-and-economics” movement made the courts more reasoned and rigorous. It also changed the verdicts judges handed out. Research has found that those exposed to its ideas are more opposed to regulators and less likely to enforce antitrust laws, and tend to impose prison terms more often and for longer.

Links between economics and the law have long been studied. In “Leviathan”, published in 1651, Thomas Hobbes wrote that secure property rights, which are needed for a system of economic exchange, are a legal fiction that emerged only with the modern state. By the late 19th century, legal fields that overlapped with economics, such as matters of taxation, were being analysed by economists.

With the arrival of the law-and-economics movement, every legal question was suddenly addressed in the context of the incentives of actors and the changes these produced. In “Crime and punishment: an economic approach” (1968), Becker argued that, rather than being a balancing-act between punishment and the opportunity for reform, sentences act mainly as a deterrent: the literal “price of crime”. Harsh sentences, he argued, reduce criminal activity in much the same way as high prices cut demand. With the caveat that a greater chance of arrest is a better deterrent than longer prison sentences, Becker’s theorising has since been borne out by decades of empirical evidence.

Too steep?

In the movement’s early days, “the legal academy paid little attention to our work”, recalls Guido Calabresi, a former dean of Yale Law School and another of the field’s founding fathers. Two things changed this. The first was Mr Posner’s bestselling textbook, in which he wrote that “it may be possible to deduce the basic formal characteristics of law itself from economic theory.” Mr Posner was a jurist, who wrote in a language familiar to other jurists. Yet he was also steeped in the economic insights of the Chicago school. His book successfully thrust the law-and-economics movement into the legal mainstream.

The second factor was a two-week programme called the Manne Economics Institute for Federal Judges, which ran from 1976 until 1998. This was funded by businesses and conservative foundations, and involved an all-expenses-paid stay at a beachside hotel in Miami. It was no holiday, however, even if those who went nicknamed the conference “Pareto in the Palms”. The curriculum was extremely demanding, taught by economists including Friedman and Paul Samuelson, both of whom had won Nobel prizes.

image: the economist

By the early 1990s nearly half the federal judiciary had spent a few weeks in Miami. Those who attended included two future justices on the Supreme Court: Clarence Thomas (an arch conservative) and Ruth Bader Ginsburg (his liberal counterpart). Ginsburg would later surprise colleagues by voting with the conservative majority on antitrust cases, applying the so-called “consumer welfare standard” championed by the Manne programme. This states that a corporate merger is anticompetitive only if it raises the price or reduces the quality of goods or services. Ginsburg wrote that the instruction she received in Miami “was far more intense than the Florida sun”.

In a paper under review by the Quarterly Journal of Economics, Elliot Ash of eth Zurich, Daniel Chen of Princeton University and Suresh Naidu of Columbia University treat the Manne programme as a natural experiment, comparing the decisions of every alumnus before and after their attendance at the conference. They then use an artificial-intelligence approach called “word embedding” to assess the language in judges’ opinions in more than a million circuit- and district- court cases.

The researchers find that federal judges were more likely to use terms such as “efficiency” and “market”, and less likely to use those such as “discharged” and “revoke”, after time spent in Miami. Manne alumni took what the authors characterised as the “conservative” stance on antitrust and other economic cases 30% more often in the years after attending. They also imposed prison sentences 5% more frequently and of 25% greater length. The effect became stronger still after 2005, when a Supreme Court decision gave federal judges greater discretion over sentencing.

That researchers are turning the unforgiving lens of economic analysis on law and economics itself is a promising trend. The dismal science has come a long way since the heyday of the Chicago school. Thanks in large part to the empiricism of behavioural economics, it is less wedded to abstractions like the perfectly rational actor. This has softened some of the Chicago school’s harsher edges. But it will nevertheless take time for judges to modify their approach. As Mr Ash notes: “The Chicago school economists may all be retired or dead, but Manne alumni continue to be active members of the judiciary.” In courtrooms across America, Mr Posner’s influence will live on for decades to come.

Wednesday, 15 May 2013

Waist to height ratio 'more accurate than BMI'



Your waist should be no more than half the length of your height, according to experts who claim that having too large a trouser size can dramatically shorten your lifespan.

Waist to height ratio 'more accurate than BMI'
Keeping your waist circumference to less than half of your height can help prevent the onset of conditions Photo: Alamy
Measuring the ratio of someone's waist to their height is a better way of predicting their life expectancy than body mass index (BMI), the method widely used by doctors when judging overall health and risk of disease, researchers said.
BMI is calculated as a person's weight in kilograms divided by the square of their height in metres, but a study found that the simpler measurement of waistline against height produced a more accurate prediction of lifespan.
People with the highest waist-to-height ratio, whose waistlines measured 80 per cent of their height, lived 17 years fewer than average.
Keeping your waist circumference to less than half of your height can help prevent the onset of conditions like stroke, heart disease and diabetes and add years to life, researchers said.
For a 6ft man, this would mean having a waistline smaller than 36in, while a 5ft 4in woman should have a waist size no larger than 32in.
Children in particular could be screened as early as five using the waist-to-height ratio to identify those at greatest risk of obesity and serious health conditions later in life, it was claimed.
Researchers from Oxford Brookes University examined data on patients whose BMI and waist to height ratio were measured in the 1980s.
Twenty years later, death rates among the group were much more closely linked to participants' earlier waist-to-height ratio than their BMI, suggesting it is a more useful tool for identifying health risks at an early stage.
By comparing the life expectancies of various groups of people at different waist-to-height ratios, they were able to calculate how many years of life were lost as people's waistlines increased.
For example, a man aged 30 with a waist-to-height ratio of 0.8, representing the largest one in 500 men, stood to lose 16.7 years of life due to their size.
A 50-year-old woman with the same ratio, accounting for about one in 150 women of the same age, would lose 8.2 years of life on average.
Dr Margaret Ashwell, whose previous research has suggested that the waist-to-height ratio could be a better tool than BMI for predicting a range of diseases, presented her findings at the European Congress on Obesity in Liverpool.
Measuring someone's waist is important because it accounts for levels of central fat which accumulates around the organs and is particularly closely linked to conditons like stroke and heart disease.
She said: "If you are measuring waist-to-height ratio you are getting a much earlier prection that something is going wrong, and then you can do something about it.
"The beauty is that you can do it in centimetres or inches, it doesn't matter. We have got increasing evidence that this works very well with children as well, because whilst they grow up their waist is growing but also their height."