My Sparrow Dead and Cold

I have recently been rather drawn into the world of electrosenstivity and found that passions run high. But loudness of voices and strength of convictions rarely match closely to soundness of argument. Indeed, high voices, closed minds and poor debate are a good indicator that quackery might be at work.

I have been quite critical of those that support electrosensitivity suffers for being so hostile to the idea that people who believe that their ill health is due to Wi-Fi and mobiles may be suffering from psychological problems, or just be plain wrong in their self-diagnosis. Roderick, who runs Eletrosensitivity UK, is particularly shrill at those who put forward psychological explanations of some of the symptoms. He appears to believe that such possibilities somehow diminish his supporters even though their illness would be just as real, no matter what the cause.

Even if some people were found to really be affected by electromagnetic radiation (the possibility is there) does that mean that all people reporting symptoms are suffering because of this? It is a good bet that some, if not all, may well be suffering from some sort of neurosis. Does Roderick want to write these people off? Compassion alone, requires a more open minded approach.

Powerwatch, the other main site dealing with this issue, has a similar, if not quite so hysterical, approach. There is a characteristic clinging to any evidence, no matter how circumstantial, to support the idea that electromagnetic radiation is very bad for us. Little balance or careful analysis appears to take place. A hundred pieces of research with flawed conclusions, unrepeatable results, or out-of-context data, does not add up to a strong case.

Let’s look at just one example from a screaming headline in the Daily Mail: Mobile phone masts blamed over the vanishing sparrows. It reports a Belgian study that shows a correlation between the number of sparrows in an area and the proximity to mobile phone masts. The closer to mast the lower the number of sparrows. And of course, there is instant blame from all quarters that mobile masts are killing our lovely garden sparrows.

But there is a big problem. According to the British Trust for Ornithology, sparrows have been in decline for many years. Here is a graph of their numbers…

Now, the sharp eyed amongst you will notice a few things. The decline started well before the mobile was invented and then appears to level off as mobile take-up was becoming near exponential. For completeness, here is another graph, showing growth in mobile phone usage, which undoubtedly correlates with environmental exposure to mast emissions.

Not a good correlation then. Something else is affecting the sparrows. The RSPB believe the decline is due to tidier gardens and better maintained housing which reduces nesting sites and availability of food. This is, at least, a plausible hypothesis.

But even when there is correlation we have to be cautious. Looking at the graph below, we can see that Buzzards have increased dramatically in the UK and the increase is a much closer fit to the growth of mobile phones?

Do mobile phone masts give buzzards super breeding powers? Is the correlation real? Maybe there are other factors at work, like masts providing ideal nesting places, or supplying dozens of dead sparrows for food, or maybe there is no real cause and effect at all. It could just be chance and unrelated.

So, what can explain the Belgian study? Well, one thing stands out is that the researchers do not appear to have considered other confounding factors.

A confounding factor in a study is a variable which is related to one or more of the variables defined in a study. A confounding factor may mask an actual association or falsely demonstrate an apparent association between the study variables where no real association between them exists. If confounding factors are not measured and considered, bias may result in the conclusion of the study.

So what confounding factors might there be? Maybe sites where mobile phones are put are not liked by sparrows. They may lack trees, nesting spaces, food or have higher human activity. The places carefully chosen to erect masts, may just not be good sparrow hanging-out places. Masts could be associated with problems for sparrows that have nothing to do with electric field strength. The conclusions from the research should be to look at more detail at some of these factors, not jump to conclusions about the harmful effects of electric fields from masts.

Sir Austin Bradford Hill wrote a paper 40 years ago that sets out the standards for looking at how to interpret such correlations. This must count as one of the most influential essays in medical history and is probably responsible for saving more lives than many of the drugs on the market today. Such is the power of pure reason. From the thoughts in this essay came the ability to discover real cause and effect relationships between environmental effects (such as mobile phone emissions) and health. It uncovered the dangers of smoking, the causes of many cancers and many occupational hazards.

The paper describes the tests you should apply to discover real relationships, and avoid drawing wrong conclusions from confounded or chance correlations. These tests include looking for the strength of the correlation, its consistency with other data, a clear dose-response relationship, plausibility, coherence and experimental confirmation. Ignore these tests and you will be led up the garden path.

The sparrow study does not have these things yet. More work could provide them. An experiment might help, such as setting up phone masts, with some operational and some not, and see the effect on local sparrow populations. This would be expensive, but would provide good confirming evidence. Should we be calling for more research?

It depends what your motives are. Do you want to find out why sparrows are declining? Or do you want to cling to any piece of evidence, no matter how poor and circumstantial, that might just support your convictions that mobile phones are killing us?