Thursday, January 10, 2013

Critical Thinking Thursday: Statistics Mean Nothing

Today's Critical Thinking Thursday post is a bit late as I was busy learning an important lesson:  Always check the oven before pre-heating it.  I had left something in it previously and completely forgotten about it.  I didn't notice this until turning on the oven to pre-heat for a pizza....and copious amounts of smoke began billowing from the oven.  Oops.  We retreated to Buffalo Wild Wings until the smoke cleared -- hence the late post.

Anyway, today I want to talk about this graphic:


I saw this kicking around on Facebook and it's a beautiful example of the way you can twist statistics around to say basically anything you want.  So, let's go step-by-step and see how you can critically examine this, shall we?


  • First off, let's check that the figures are even accurate.  Since the graphic doesn't site a source for any of these numbers, we'll have to check them manually.  When searching, you'll want to find a website that doesn't have its own agenda (for obvious reasons), so we'll want something with some objective credibility.  
  • Let's take a look at that 195,000 figure first.  First off, the data is 10 years old.  Second, the actual causes of death are "failure to rescue, bed sores, postoperative sepsis, and postoperative pulmonary embolism".  So now we have that figure explained a bit more clearly.  
  • Now, the assault rifle figure.  It took some digging to find the primary source on this one, but it looks like it's from the FBI. (Interestingly, based on the FBI data, the figure quoted for knives is actually very low -- the figure quoted here is 1,694 for stabbing deaths).  
  • The 12,000 drunk driver fatalities appears to be from this site here, which offers an average (not the exact figure).  
OK.  Now that we've found the source of each figure, let's look at a few interesting things about how the data is compiled and represented, shall we?
  • By specifically choosing assault rifles, the graphic down plays the severity of gun violence in general.  According to the CDC, firearms account for 31,347 deaths.  Of these, according to the FBI, 12,664 were homicides.  The others could range from accidents (children handling guns, hunting accidents) to suicides.  
  • This means that gun homicide (in general) is actually more dangerous than drunk driving.  Someone with a different political stance could make a different graphic using exactly the same sources and come to that conclusion -- more gun murders happen annually than drunk driving deaths.  
  • Incidentally, according to the CDC, the total number of vehicle fatalities (not just drunk drivers) is 34,485, which is still higher than the total number of firearm fatalities.  Therefore, someone could, again, take the same data and make a new graphic showing that cars are more dangerous than guns (but the margin is much narrower).  
The point of all this isn't to take a side one way or the other about gun control.  The point is to show that this graphic -- which seems very straightforward -- presents its figures in a way that supports the point it wants to make.  This is the dangerous thing about statistics:  On their own, they don't actually mean anything.  The numbers have to be interpreted.  As you can see, different people can take the exact same data and extrapolate completely different interpretations from it.  

So the next time you're faced with a graphic or statistic, I invite you to take a few extra minutes to think critically about it before sharing.  Ask yourself:  Where are they getting these numbers?  Are they accurate?  Is the source reputable?  If you look at the data yourself, do you get a different interpretation?  How many other ways can those numbers be interpreted? 

3 comments:

  1. Good article that echoes many ideas I agree with while concluding the opposite. Lets use some critical analysis to look at this post:

    In response to the 195000 deaths attributed to Medical Malpractice it is noted that the data is 10 years old and refers to many different ways you can die at the hands of the medical establishment. There is a distinctive negative implication to the data being ten years old - as if that would actually make any significant difference in the figure. Generally the tone suggests that the rational person once having the "figure explained a bit more clearly" would see this is inflated somehow. Assuming I agree that it is a clearer explanation why would I think it changed anything? Same number dead. Same class of cause. Same relative weight in the graph...

    Next the analysis refers to assault rifle figure asserting the original author's apparent intent to downplay gun violence. However, I would note that since the national discussion at the moment is control of assault weapons it is not at all misleading (or minimizing) to assert the actual death toll attributable to them. I agree its important to keep a proper perspective about all gun violence. So how about we include the number of people killed by our govt in illegal war in the middle east in the discussion as well. It seems to me that bringing the real numbers of gun death into the argument would be more in support of limiting our government's access to guns rather than its citizens. We could argue that all the guns belong with the govt because after all, they are currently doing the most killing of all sources and are best at it but that's pretty perverted. The analysis also notes the knife figure is low (in the midst of a generally adversarial claim) which seems to be attempting to mask the fact that the knife figure further supports the idea being presented by the original author.

    The analysis goes on to aptly note how ridiculously statistics can be distorted. I applaud the point. However once again the biases of the analyzer seem to be leaking through in the closing remarks. Indeed, the slant of this post appears to be very clear. Hold up a claim, then say its false (while claiming no bias).

    My critical analysis says that the above analysis serves no purpose (in the immediate topic frame) other than to cloud the facts and remove conviction from those who might read it and be swayed. Using our critical analysis tools I am suspicious.

    I believe the original article succeeds in (reasonably accurately portraying the relative importance of the issues even though it could have been done better. Indeed I would assert that a nearly identical graph could be produced using current "accurate" numbers and it would show the same thing: The odds of you being killed by an assault weapon are substantially lower than just about any other way you can die - and therefore if we are going to claim this process we are engaged in somehow rational - how can we justify the level of national upheaval and energy expenditure for a problem that is so small relatively speaking. Even the most cursory look at the ways we die leads to the conclusion that assault weapons are not a problem. Deep research makes it even more apparent.

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  2. BTW I am anti-gun. I don't own any and won't - I wish no one had them (especially our government) - but they do have them. I wish people didn't kill people but they do whether they have guns or not. But I also don't trust the federal government or any government to actually look out for me. They have proven through their actions and even overt assertion that that is not their intent. I have come to defend the 2nd amendment (after ridiculing it for years) after trying to find support for the ideas behind amending it. I got mad and started trying to find ways to justify my blame In the end I failed to find that support and concluded that guns suck people who kill people suck, governments suck - but for the moment at least - we are stuck with them and gun control doesn't actually work, and most importantly there are dozens of problems much bigger that we should be focusing all this energy on if we really believe the rhetoric we are all spouting. i.e. if we really want to save lives there are many much better ways.

    That's my bias. I don't have the energy to try to determine what Mr. Bodine's bias actually is. I like to believe the best and so I will assume that it was really just a poor job of trying to altruistically educate critical thinkers. Suffice it to say that he appears pro-gun control and the analysis while purporting to be a balanced attempt to educate critical thinkers seems much more likely to serve only to fog the gun debate.

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    Replies
    1. Thanks for stopping in and providing your input. My goal in these Critical Thinking Thursdays posts is to encourage free inquiry and questioning, so I always appreciate it when I see that happening :)

      Honestly, I didn't really intend for this post to be about gun violence as such. I do have opinions on the topic, and perhaps my bias leaked through, but that was not my intent.

      I actually had a different graphic I had considered taking apart instead, on a completely different topic (involving shark attacks), but I opted for this one because I had it handy.

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