"XKCD: Correlation"

"XKCD: Correlation" via Jyrinx on flickr

Ok, there are a couple of things that crop up in the “main-stream” media that have just rubbed me the wrong way for quite a while, so I’m gonna take this opportunity to sound off a bit…. from a working scientists perspective.

First thing is all of the news stories that we hear about this medical study and that medical study, all of which seem to eventually be at odds with each other or that tell us “eating rutabagas appears to lessen your chance of getting eyebrow cancer by 0.4%”  First of all, I’m not going to rag on the people who do the studies.  They work hard and are generally intelligent people (maybe not the whiny, cry baby pre-meds who used to take my non-calculus physics classes, but most of them).  They do good work and uncover interesting things.

The problem lies in the P.R. people and the media people who grab hold of their results and plaster them (National Enquirer style) all over the papers, magazines and TV, misrepresenting the actual research findings.  What do the researchers REALLY do and what do they find?  Well, this kind of research mostly involves sending questionnaires to a whole bunch of people, or asking for anonymous medical records from doctors and clinics.  The researchers then pour over the mass of stuff and record who had cancer of the whatever, what did they usually eat for breakfast, what was their shoe size, how often did they drink, and on and on, recording a whole lot of details.

All of this is then fed into a program that calculates lots and lots of esoteric statistics and tells the researchers when there are “correlations” between things.  This means something like “of the people who had bladder cancer, more than we would expect had larger than average feet”.  That’s a correlation.  Unfortunately, it’s not what is known as a “causal” relationship.

A “causal” relationship is something like “because the Earth has a gravitational field, the ball I dropped just hit the ground”.  Causal relationships are just like the word sounds…. an affect that happens because of a KNOWN and UNDERSTOOD cause.  In my previous example (big feet and bladder cancer), there is no “cause”.  I have a friend who does research on plant growth.  Whenever he reviews a scientific manuscript and encounters something like “It was observed that time plays a key role in the growth of soy beans”, he turns beet red and starts to rant “Time!?  Time!!?  Soy beans don’t wear damn wrist watches!  Time has nothing to do with it!”  That’s a case of mistaking a correlation (time and growth) for a causal one.  In actuality, the real causal relationship is probably between growth and accumulated sun light.

So the next time that Scott Pelley or Charles Gibson or Brian Williams reads a story that says “researchers today announced that a study found people who travel more tend to live 3 months longer than home-bodies” Don’t run out and spend the retirement funds on airline tickets!  That’s a correlation, not a causal relationship!  It’s quite likely that something else is responsible for those extra 3 months…. like the fact that people who can afford to travel have better health care!

Second thing.  I’m sick and tired of grand standing politicians, PAC spokes-critters, and the like “flagging” government waste in so-called ridiculous research projects.  It’s yet another case of people who know little or nothing about the actual science, telling everyone what the science is!

The latest case in point is the flap about a federal grant which funded some cancer research.  The researchers wanted to know how nicotine levels and their changes affected cancer rates.  THAT is the science.  The TeaBaggers, however latched on to a portion of their methodology and twisted IT to be the science behind the grant.

The traditional way for this research to be done would be to recruit a large number of subjects, have them all report to a clinic where blood and tissue samples are taken and stored until they could be analyzed.  This would involve lots of inconvenience to the subjects (who would have to schlep themselves to the clinic site or sites).  It would require hiring med. techs. to take the blood and tissue samples.  It would require freezing and preserving the samples until they could be analyzed.  All of this would have been costly…. very costly!

Instead, some clever person on the research team realized that the nicotine levels could be deduced by analyzing hair samples and that finger and toe nails were essentially the same thing!  Instead of all the fuss and muss I described above, they simply asked their subjects to clip, save, and mail in their finger and toe nails every month.  HUGE saving of money, time, and effort!  A++ for creativity in my book!

But Nooooooo!  The ever so smart TeaBaggers, Grover-worshipers, and Koch-heads saw the words “toe nail” and their great big brains said “Why that’s silly!  I’ve never learned anything from my toe nail clippings and since I’m the smartest person god ever made, no one else can either!”  Thus they went on a rampage against wasteful “guvmint” spending.  Toe nail clippings INDEED!  Not with my money!

"Grasshopper Sex"

"Grasshopper Sex" by Ben Garland on flickr

Another example that I’ve heard was outrage about a federal grant to study “the sex life of grasshoppers”.  Do they (the outraged) know just how much crop damage grasshoppers do in the U.S.? or Africa? or China?  If we could “interrupt” their reproductive cycle (I meant the grasshoppers, but maybe we should try it on the TeaBaggers too!), we might get a leg up on some of the famines that seem to happen every few years!

Okay, that was pretty snarky.  They were really trolling for silly sounding phrases like “mailed in toe nail clippings” or “grasshopper sex” just to cause a fuss and get ANYTHING and EVERYTHING de-funded.  Still, it just baffles me that people hear this outcry about wasteful and silly research from people who’s closest association with science is as a fund raiser for The Center for Intelligent Design and take it for truth.  DON’T LISTEN TO THEM!  They don’t know what they’re talking about!

Getting federal research money is a very tough thing.  I know, because I try to do it all the time.  I also review research proposals for NASA, DOE, DOD, NSF, EPA, and a few others.  The bad and silly ones don’t get funded!  So the next time that you hear someone in an expensive suit rail against wasteful government research projects, just ask them “Why do you like the cancer that killed my Grampy” or “Why do you want all of gods little African babies to die from famine?”