Tag: correlation is not causation

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Statistics Statistics in the media

Most developers have never seen a successful project

Most developers have never seen a successful project

Is this bad science?  Since this is a retrospective study, there is non-random assignment for the treatment and control groups.  That introduces selection bias.  Projects that are more likely to implement a (long-winded) “waterfall” life-cycle approach are probably larger scale projects to begin with.  Correlation is not causation.  So, maybe it’s not the lifecycle approach that is the problem, but the confounding/lurking variable of project scale that is the problem.  The study should control for the size of the project to make a valid conclusion about success rate of the development approach used.  ie:  Building a large insurance processing system will use a lifecycle approach, while building a fitness app will not.  Apples to oranges, since one is much easier to be implement than the other.

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Statistics in the media

Does Exercise Really Keep You Young?

Here is an example of selection bias.    Correlation is not causation.  Those with serious illness and poor health will not be in the active group.  The limits of an observational study vs. a properly controlled experiment with random assignment.

Does Exercise Keep You Young?

 

 

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Education Statistics in the media

Ivy degrees and income: Correlation vs. Causation?

Krueger and Dale studied what happened to students who were accepted at an Ivy or a similar institution, but chose instead to attend a less sexy, “moderately selective” school. It turned out that such students had, on average, the same income twenty years later as graduates of the elite colleges. Krueger and Dale found that for students bright enough to win admission to a top school, later income “varied little, no matter which type of college they attended.” In other words, the student, not the school, was responsible for the success.

 

http://www.brookings.edu/research/articles/2004/10/education-easterbrook

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Statistics in the media

Do music lessons make you smarter?

 

http://www.nytimes.com/2013/12/22/opinion/sunday/music-and-success.html

  • Year after year, researchers report associations between children’s participation in music classes and better grades, higher SAT scores and elevated cognitive skills. It’s also well known that many successful adults played instruments as children. On the basis of such evidence, you might assume that music education helped cause such positive outcomes.  That is a misguided assumption.
  • Correlation does not imply causation.   Parents who can afford private music lessons might also be more likely to read to their children than to sit them in front of the TV. Children willing to practice an instrument daily might also persevere longer than their peers on their math homework.
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Statistics in the media

Harvard researchers challenge results of obesity analysis

Weight and mortality

The studies that Flegal did use included many samples of people who were chronically ill, current smokers and elderly, according to Hu. These factors are associated with weight loss and increased mortality.

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Statistics Statistics in the media

1940s: Ice cream causes polio!

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Statistics Statistics in the media

Is the Family Dinner Overrated?

But does eating together really make for better-adjusted kids? Or is it just that families that can pull off a regular dinner also tend to have other things (perhaps more money, or more time) that themselves improve child well-being?

Is the Family Dinner Overrated?