Wednesday, June 04, 2008

Clear path to clearer thinking

Critical thinking is one of the key "valued added" components we can offer to differentiate our content from generic, commodity news and data that floods the infosphere.

An important aspect of that is understanding probability and statistics. Doing the Democrat delegate math made it clear months ago Hillary Clinton was almost certainly not able to win, but superficial reports kept talking about the "razor-thin" margin between them and so forth. Similarly, we often buy into conventional wisdom and shallow thinking when we'd be doing readers much better service by aplying tough-minded, clear-eyed analysis instead.

Here's a post in which Cory Doctrow writes in the Guardian about how and why humans are willing to gamble in casinos and stand in long security lines – even though neither is likely to pay off for them. It's an entertaining read, and also a powerful lesson.

Here's a taste;please forgive Cory for his exclamation point (he's young):

Our innumeracy means that our fight against these super-rarities is likewise ineffective. Statisticians speak of something called the Paradox of the False Positive. Here's how that works: imagine that you've got a disease that strikes one in a million people, and a test for the disease that's 99% accurate. You administer the test to a million people, and it will be positive for around 10,000 of them – because for every hundred people, it will be wrong once (that's what 99% accurate means). Yet, statistically, we know that there's only one infected person in the entire sample. That means that your "99% accurate" test is wrong 9,999 times out of 10,000!


  1. Wait a sec. The last sentence in your excerpt is totally false. The test is still 99 percent accurate (no quotes) because it's right 990,001 times out of a million. Wrong, 9,999 times out of a million, not out of 10,000. Or is that his point? That we believe wrong statments like that?

  2. Anonymous7:06 AM

    I noticed that too!
    I think the exclamation point is understood to mean " When you ignore the 990,000 accurate results!"