Consensus Cons

Consensus Cons

Murray Op Ed in Tech Central Station
May 27, 2003

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It is a regrettable fact that most of the public is ignorant about science—not just about current scientific theories and experiments, but about the scientific method in general. Yet science affects virtually every aspect of our lives. Nevertheless, we recognize this failure and have done something about it. As a society, we have delegated our duty to learn about science to the media. Yet when the media are pulled in other directions by other influences on them, we are left thinking that we know what's going on in the world when we don't. And that's a problem. This is illustrated in a new report (sadly not available online) from <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Cardiff University in Wales, which examined public knowledge of scientific issues in the United Kingdom. In particular, it examined the public's understanding of the issues surrounding the MMR vaccine, which has been alleged to be linked with a rise in autism diagnoses among children. In the month after the story broke in January 2002 there were over 300 media reports on the issue, a classic example of a media feeding frenzy over a scientific issue. Over two thirds of these stories mentioned the supposed link between the shot and the illness. As a result, 53 percent of the British public interviewed at the height of the coverage agreed with the suggestion that, as there was equal media coverage of the two sides of the debate, there must be equal evidence to support each case. This is far from the truth. Study after study has been unable to find any significant or causal link between the MMR vaccine and autism. Scientists are therefore virtually unanimous that there is no cause to worry about the shot harming children in this way. The study found, however, that almost half of television reports and over two thirds of "quality" newspaper stories failed to mention this important fact. It is, of course, generally a good rule in journalism that when one view is stated, the opposite view should be given time or space to balance the coverage. Yet in this scientific case, as the study's authors say, "Attempts to balance claim about the risks of the MMR jab tended merely to indicate that there were two competing bodies of evidence." By attempting to meet one journalistic standard in giving a balanced picture, the journalists failed to meet other standards about giving the proper context to the claims. Does it therefore follow that reference should always be made to the scientific consensus? Not necessarily. Media reports about climate change, for instance, regularly refer to the consensus of scientists that man is brining about detrimental climatic change. Lists of Nobel laureates and references to the Intergovernmental Panel on Climate Change abound in reports on "global warming." Yet here the context fails to reflect the state of the argument. In the case of MMR, the scientific method had progressed along the ideal model: theories were proposed, experiments performed to test the theories, outcomes observed, data collected and analyzed and a consensus reached that the theories held up or needed to be rejected. In the case of global warming, however, we are necessarily still at the theory level. Like it or not, we cannot perform experiments with climate. There is no parallel Earth to act as a controlled environment. So we can only progress by developing theories into models. These models can themselves only be tested by comparison with observed data, and, as we see regularly, the models and the data often do not agree. For instance, data from satellite and weather balloons indicate that certain areas of the atmosphere are not warming as the models suggest they should. Some suggest that this means that the data, not the models, are inadequate. As there exist many questions as to the fit between the models and the data it cannot truly be said that a scientific consensus has emerged that they are accurate. All we have is a theoretical consensus that may or may not stand up to the tests the theories need to be subjected to. To put it in MMR terms, it is as if the link between the vaccine and autism had been proposed, but the scientific consensus was that there was no such link, before any experiments had been done to prove it. The journalists' approach to allowing both sides equal time would have been more justifiable, and perhaps even correct, if that had been the case. So, in the case of MMR, journalists gave equal time when they should have pointed out the general scientific agreement. In the case of climate change, the journalists are pointing out scientific agreement when they should be giving equal time. It is the public who is suffering in both cases. When it comes to climate change, two-thirds of people interviewed by the Cardiff team said that the hole in the ozone layer causes global warming. Perhaps it is time we stopped delegating our scientific understanding to journalists and starting learning it for ourselves.