DailyDirt: Correlation Is Not Causation

from the urls-we-dig-up dept

Big data is a term that's been getting some buzz as the next thing that's going to change everyone's lives (for better or worse, depending on how you look at it). Having a lot of data doesn't necessarily mean you also have a lot of useful knowledge. Garbage in, garbage out, so they say. And making correlations is easy compared to finding a direct causal relationship. However, that hasn't stopped (so-called) journalists from writing misleading headlines. If you hate correlations being mistaken for causation, submit examples you've seen in the comments below. Here are just a few to start off. If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post via StumbleUpon.
Hide this

Thank you for reading this Techdirt post. With so many things competing for everyone’s attention these days, we really appreciate you giving us your time. We work hard every day to put quality content out there for our community.

Techdirt is one of the few remaining truly independent media outlets. We do not have a giant corporation behind us, and we rely heavily on our community to support us, in an age when advertisers are increasingly uninterested in sponsoring small, independent sites — especially a site like ours that is unwilling to pull punches in its reporting and analysis.

While other websites have resorted to paywalls, registration requirements, and increasingly annoying/intrusive advertising, we have always kept Techdirt open and available to anyone. But in order to continue doing so, we need your support. We offer a variety of ways for our readers to support us, from direct donations to special subscriptions and cool merchandise — and every little bit helps. Thank you.

–The Techdirt Team

Filed Under: big data, brain, causation, correlation, gigo, iq, journalism, pet peeves, success
Companies: facebook


Reader Comments

Subscribe: RSS

View by: Time | Thread


  • identicon
    Anonymous Coward, 2 Jul 2014 @ 5:09pm

    "You may be interested to know that global warming, earthquakes, hurricanes, and other natural disasters are a direct effect of the shrinking numbers of Pirates since the 1800s."

    http://www.venganza.org/about/open-letter/

    reply to this | link to this | view in chronology ]

  • icon
    Sheogorath (profile), 2 Jul 2014 @ 5:49pm

    I got one!

    People claiming that the MMR causes Autism just because the vaccine is given around the time that late-oneset Autism first appears.

    reply to this | link to this | view in chronology ]

  • icon
    Chronno S. Trigger (profile), 2 Jul 2014 @ 7:20pm

    Go to news.google.com and click the health section. I guarantee you'll find correlation articles. I just did and apparently dark chocolate (not milk chocolate) helps people with peripheral artery disease walk. Doesn't matter that they only tested on 20 people or that the change was only 11%.

    reply to this | link to this | view in chronology ]

    • identicon
      Anonymous Coward, 2 Jul 2014 @ 10:22pm

      Re:

      If the study controls for reasonable factors and the 20 subjects were validly random, then it could be legit - at least as an initial study.

      The more subjects a study needs to prove a point, the less you should trust the results. Psychiatric drug field studies routinely twiddle the numbers to get the results they want by combining samples from beneficial (lucky?) studies into cohorts that don't exhibit any positive reponse to show that on average, patients from the two cohorts show a positive response!

      Citation: http://www.youtube.com/watch?v=A3YB59EKMKw I *think*. I'm at work now so can't confirm, but I'm pretty sure that's the one.

      reply to this | link to this | view in chronology ]

      • identicon
        Anonymous Coward, 3 Jul 2014 @ 5:09am

        Re: Re:

        "The more subjects a study needs to prove a point, the less you should trust the results."


        "Needs to prove a point", implies this is not science, but rather a marketing ploy.

        In a well constructed experiment or "study", as the sample size increases so does the precision.

        reply to this | link to this | view in chronology ]

        • identicon
          Anonymous Coward, 3 Jul 2014 @ 8:09pm

          Re: Re: Re:

          "Needs to prove a point", implies this is not science, but rather a marketing ploy.

          Well, yes.

          In a well constructed experiment or "study", as the sample size increases so does the precision.

          Well, no. In a well constructed experiment, precision will remain constant regardless of the sample size, but the resolution of the findings may be different.

          eg- assuming correct randomisation and good controls across all sample sizes, a study of 20 subjects with no negative outcomes means you can confidently state a rate of "less than 1 in 20". Take it up to 20,000 subjects, you might find 100 negative outcomes relative to control, meaning you can refine your rate of

          reply to this | link to this | view in chronology ]

          • identicon
            Anonymous Coward, 3 Jul 2014 @ 9:23pm

            Re: Re: Re: Re:

            ate my comment!

            meaning you can refine your rate of

            reply to this | link to this | view in chronology ]

          • identicon
            Anonymous Coward, 3 Jul 2014 @ 9:23pm

            Re: Re: Re: Re:

            take 2...

            meaning you can refine your rate of less than 0.05 to less than 0.01 (or lower? My statistics-fu is weak)

            Of course, neither study proves that the rate across the entire population isn't really 0.5, but that's what randomisation is supposed to (try to) address. Alternatively, even if the rate across the study population is accurate, it can be difficult to determine if a particular person might fit into that population or not.

            reply to this | link to this | view in chronology ]

          • identicon
            Anonymous Coward, 4 Jul 2014 @ 6:49am

            Re: Re: Re: Re:

            "precision will remain constant regardless of the sample size, but the resolution of the findings may be different"
            - This is incorrect. You assume the sample size quantity exceeds the quantity of possible unique results. When the aforementioned is not the case, increased resolution would only provide more detail of an incomplete data set.


            "assuming correct randomisation"
            - This is an attempt at simplifying the problem, as clearly there is no such thing as "correct randomization"

            reply to this | link to this | view in chronology ]

  • identicon
    Lawrence D’Oliveiro, 3 Jul 2014 @ 12:29am

    So What If Correlation Is Not Causation?

    How does that cause you to conclude anything?

    reply to this | link to this | view in chronology ]

  • identicon
    Anonymous Coward, 3 Jul 2014 @ 2:45am

    reply to this | link to this | view in chronology ]

  • identicon
    Anonymous Coward, 3 Jul 2014 @ 5:14pm

    1) An increase of global surveillance since 9/11 by the NSA correlates with a decrease in terrorist attacks killing more than 2,500.
    Conclusion: surveillance works, so we should do more.

    2) An increase of global surveillance since 9/11 by the NSA correlates with an increase in global terrorist activity.
    Conclusion: surveillance would work if we could do more.

    Of course, #2's predicate might actually involve legitimate causation...

    reply to this | link to this | view in chronology ]


Add Your Comment

Have a Techdirt Account? Sign in now. Want one? Register here



Subscribe to the Techdirt Daily newsletter




Comment Options:

  • Use markdown. Use plain text.
  • Remember name/email/url (set a cookie)

Close

Add A Reply

Have a Techdirt Account? Sign in now. Want one? Register here



Subscribe to the Techdirt Daily newsletter




Comment Options:

  • Use markdown. Use plain text.
  • Remember name/email/url (set a cookie)

Follow Techdirt
Insider Shop - Show Your Support!

Essential Reading
Techdirt Insider Chat
Recent Stories

This site, like most other sites on the web, uses cookies. For more information, see our privacy policy. Got it
Close

Email This

This feature is only available to registered users. Register or sign in to use it.