Anecdotes are never evidence...unless they're your own.
by Chad Jones
March 16, 2013
In general, skeptics understand the importance of making evidence-based decisions. They look for controlled studies that have been properly conducted and insist that they won't accept anecdotes as evidence. In theory that is best practice, but the reality is it's downright impossible to do. There isn't a study for every decision we would make, so more often than not our decisions are based purely on anecdote (we've seen that X happens when we do Y, so we assume that X causes Y).
I've written in the past about essential oils. Their health benefits are largely exaggerated and they've been shown in several studies to have limited to no anti-viral, anti-fungal, or anti-bacterial effects. And yet, as expected, when I published the post the comment section filled up with anecdotes - often these claims were prefaced with "I know this is just an anecdote, but...". To me this meant that they were aware that evidence should trump anecdote, but were unwilling to accept the evidence over their own anecdote. So do these offenders deserve to be thrown in skeptic jail for their crimes? I don't think so.
It's easy to dismiss anecdotes that aren't your own since you didn't experience them. However, our minds are so easily fooled by our own senses (I've written many posts on my own blog about how our intuition can be wrong). Not only are we easily fooled, but we're bad at knowing (or accepting) that we have been fooled. We assume (either consciously or otherwise) that our own experiences as more important than the experiences of others. It seems, then, that anecdotes never pass for evidence...unless they're your own anecdotes.
This isn't to say that anecdotes are correct when they're your own, but instead that they are easier to accept when they're your own. About a month ago Josh DeWald wrote a two part article on anecdotes and their place in science. In part 1 he linked to this wikipedia article on cognitive bias. If you haven't read through it I suggest it. You shouldn't be able to read through the list without finding at least one bias that you consistently fall prey to. If you think otherwise you're probably falling prey to many of them. Being skeptical, then, is more about recognizing our own irrationality than it is about pointing out the irrational thoughts of others.
by Chad Jones
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