Just how big is that effect size?

24 Jan

On Monday The Washington Post ran a story with this headline: “Teens who spend less time in front of screens are happier — up to a point, new research shows.”

What the article does not tell us (but the abstract does) is the that the study had 1.1 million participants. Well that seems like a good thing, doesn’t it?

The problem is that with a sample that large almost any correlation will be statistically significant. For example, according the Post account, the correlation between texting and happiness was r = -.05. Typically a correlation of the this magnitude would be described as “none or very weak.” 


5 Responses to “Just how big is that effect size?”

  1. Enrique Guerra-Pujol January 24, 2018 at 10:20 am #

    This looks like statistical cherry-picking! The reporters need to take a statistics class or check out Deborah Mayo’s blog on rigorous statistical testing: https://errorstatistics.com/?wref=bif

    • jecgenovese January 24, 2018 at 11:15 am #

      I sent a note to the Washington Post reporter, I’ll report back if she responds.

      • Enrique Guerra-Pujol January 25, 2018 at 7:18 am #

        Keep us posted!

      • Alberto Vidal Reyes June 16, 2018 at 2:01 am #

        What ?

  2. Kathy H January 24, 2018 at 3:12 pm #

    There are three kinds of lies: lies, damn lies and statistics. (British Prime Minister Benjamin Disraeli)

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