Each Cell-Phone Tower Creates 18 Babies?! The Difference Between Causation & Correlation

By Jennifer Welsh | December 17, 2010 4:27 pm

phone-towerThose people living in areas with higher numbers of mobile phone towers have more children, new research is showing (spreadsheet).  Matt Parker at The Guardian’s Notes & Theories blog did the analysis of publicly available data and found the correlation:

Could it be possible that mobile phone radiation somehow aids fertilisation, or maybe there’s just something romantic about a mobile phone transmitter mast [aka tower] protruding from the landscape?

The data show that there is a very strong correlation between the number of cell phone towers and the birth rate in communities. For every additional phone tower, there are 17.6 more babies than the national average, Parker writes in his blog post:

When a regression line is calculated it has a “correlation coefficient” (a measure of how good the match is) of 98.1 out of 100. To be “statistically significant” a pattern in a dataset needs to be less than 5% likely to be found in random data (known as a “p-value”), and the masts-births correlation only has a 0.00003% probability of occurring by chance.

With all that fancy math talk, this sounds pretty conclusive, huh? But read on.

Many studies depend on this type of correlation. When we report on them, we try to remind readers that there is a big difference between correlation and causation. This is one of those times. The link between the birth rate and the towers isn’t actually causative, as Parker explains:

Both the number of mobile phone transmitters and the number of live births are linked to a third, independent factor: the local population size. As the population of an area goes up, so do both the number of mobile phone users and the number people giving birth.

Parker suggests that misunderstandings about correlation and causation have caused people to prematurely link health problems to cell phone towers. There are neo-Luddites around the world–like the group of parents in Ontario fearing the school’s WiFi rays and pregnant women investing in “Belly Armor” to protect their unborn children–who claim that wireless technology is harming our bodies. Yet there is no good evidence that non-ionizing radiation causes anything of the sort.

Just because two events are positively correlated doesn’t mean they are necessarily linked via causation. In these types of studies, there is always a question of where the truth lies, like reports that Adenovirus 36 causes obesity in humans. The studies draw correlations between presence of antibodies to the virus and obesity, but if it is indeed causative, this link could go either way (obesity can cause immune dysfunction, making people more likely to have been infected with AD36), or the two could be completely causally unrelated, like many correlations, Parker explains:

While this does not cause a problem when using pattern-spotting as an evolved survival tool, it does cause severe problems when assessing possible health scares based on a recently uncovered correlation. For the majority of cases, correlation does not indicate the presence of causality.

Parker is releasing his data as a press release, so keep an eye on your favorite (or least favorite) news organizations to see who bites on the sham cell tower-fertility connection.

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Image: Flickr/barryskeates

  • Art Bauza

    Maybe it’s because most towers are located in lower income neighborhoods, and it’s well known that birth rates are higher among lower income neighborhoods.

  • Staar84

    Or because phone companies put more towers in higher population areas

  • Robert

    Right… this isn’t a “per capita” birthrate, it’s just total birthrate. There are more people, so there are more babies born (and more cell towers for the same larger population).

  • Steve

    Hmmm. I think maybe the real reason is that childbirth has gone wireless, and no one was informed. Anyone have a job for millions of jobless storks?

  • Josh

    On a related note, a revolutionary new study has found that cigarettes cure cancer! Pardon my french, but what a crock of s***.

    It’s well known at this point that the radiation emitted by wireless devices and their associated infrastructure damages sperm. The fact that cell towers often get put in high-density and low-income areas doesn’t mean that they “promote fertility.”

    This sounds like just another product of the corporate spin machine that continues to work hard to sow confusion and uncertainty on this issue.

    http://www.prove-it.co/
    http://www.wireless-precaution.com/main/science.php
    http://www.fullsignalmovie.com/trailer-credits.html

  • Loren Pechtel

    There’s another factor here: Where are you going to find more phones per capita–the community of young adults or a retirement community? Obviously you’ll see more phone use amongst those of reproductive age.

  • mzabetian

    RF Radiated Sperm = SuperSperm

    Next: People who text are more likely to get pregnant.

  • cell phones = death

    it has to do with younger people living in urban areas where there are so many cell phone towers and older people who are not having children living in rural areas where there are far fewer cell phone towers.

    CELL PHONES CAUSE DEATH!!! NOT LIFE!!

  • http://drmmobs.wordpress.com/ DrMobs

    I love jumping on the correlation = causation beanbag.
    Did you know:
    Lizards sunbaking on rocks cause increased ice cream consumption? (Just ignore how sunny and hot it is).
    Getting taller causes you to have more birthdays?
    Having a large vocabulary causes you to read more?
    Increasing your facial wrinkles will increase your superannuation payout?
    Hey, maybe the babies are building the cellphone towers! Are they made out of Lego?

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