Tuesday, October 16, 2012

Ignoring the evidence: politics as usual

I have not had time to write a new post of my own for some time because real life has intervened, partly in the form of my day job (a project I am working on is nearing completion, and I am also preparing several seminar talks and grading a student's thesis), and partly in the form of other inconvenient distractions (writing job applications for next year, trying to find a new apartment and so on).

I hope to find some time to rectify this in the near future, but in the meantime I thought I would reblog a post by Simon Wren-Lewis, titled When policy ignores evidence: badgers and austerity. As you can guess from the title, it deals with just two examples demonstrating the apparent incompatibility of evidence-based rationality and politics. In fact, these examples seem to show politicians not so much failing to account for the scientific evidence as deliberately ignoring it.

This is a theme I wrote a bit about here. If that piece sounded rather cynical, well, things like this are the reason why.
 When policy ignores evidence: badgers and austerity: [...] Badgers get, and spread, TB. As a result, the UK government is about to begin a large scale cull of badgers in Gloucestershire and Somerset. No one likes the idea of killing badgers. But cattle (or occasionally alpacas) dying from TB is no fun either. So the badger cull is just one of those necessary bad things that have to be done to prevent something even worse happening. Environmentalists are up in arms, but that is just because badgers look cute and cattle do not.

Except that is not what the evidence suggests. Following various small scale randomised badger culling trials, the UK government set up an independent group of scientists (the ISG) to evaluate the evidence. In 2007 the government published the report (pdf). It concluded as follows:
“The ISG’s work – most of which has already been published in peer-reviewed scientific journals – has reached two key conclusions. First, while badgers are clearly a source of cattle TB, careful evaluation of our own and others’ data indicates that badger culling can make no meaningful contribution to cattle TB control in Britain. Indeed, some policies under consideration are likely to make matters worse rather than better. Second, weaknesses in cattle testing regimes mean that cattle themselves contribute significantly to the persistence and spread of disease in all areas where TB occurs, and in some parts of Britain are likely to be the main source of infection. Scientific findings indicate that the rising incidence of disease can be reversed, and geographical spread contained, by the rigid application of cattle-based control measures alone.”
On Sunday 30 eminent UK and US scientists published a letter in the Observer. They write: “As scientists with expertise in managing wildlife and wildlife diseases, we believe the complexities of TB transmission mean that licensed culling risks increasing cattle TB rather than reducing it.” One of the signatories described the government’s policy as crazy, and suggested vaccination and biosecurity was a better solution. The Guardian reports the chair of the ISG as saying “I just don't know anyone who is really informed who thinks this is a good idea." The current government chief scientist said: "I continue to engage with Defra [the relevant government ministry] on the evidence base concerning the development of bovine TB policy. I am content that the evidence base, including uncertainties and evidence gaps, has been communicated effectively to ministers." In other words, ministers know what scientists are saying and have decided to ignore them.

So what is going on? One of the strongest pressure groups in the UK is the National Farmers Union (NFU) [...] The NFU are convinced that culling badgers will reduce the incidence of TB in cattle, and government policy is following that belief, rather than the scientific advice it commissioned. (For more details, see George Monbiot here.) The BBC reports Defra Minister David Heath as saying "No-one wants to kill badgers but the science is clear that we will not get on top of this disease without tackling it in both wildlife and cattle." Dare I say weasel words.

[...] With austerity we did not have randomised trials: we had one almost globalised trial, starting in 2010, and one eighty years earlier. The evidence this time round is becoming clear: the harmful effects are much greater than many had assumed.

[...] perhaps the two cases are not so different. The problem with austerity is that too many people of influence just know that high government debt is always and everywhere a bad thing. Too many think it is just obvious that when a country has difficulties in selling debt that must imply cutting it back as quickly as possible, in the same way that it is obvious that killing badgers must reduce the spread of TB. And perhaps too many people see badger culls as part of a battle between farmers and environmentalists, just as austerity is a weapon in a battle over the size of the state.

Maybe we are just naive in thinking that as the evidence against austerity accumulates, and as those that were once for it change their mind, the policy will change. As Wolfgang Munchau writes (FT): “As hordes of frustrated European economists know only too well, macroeconomic analysis in general does not play a role in eurozone policy making.” So the policy goes on, in both the UK and the Eurozone, and I do not like to think about what might happen in the US if Romney wins. While I would never advocate a totally uncritical acceptance of the views of scientists, we are an awfully long way from that position, as unfortunately many badgers are about to find out.

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