Comments on: Beauty Skepticism Part 3 – Anecdotal Evidence

By: professorauntie

professorauntie — Wed, 27 Jan 2010 20:31:28 +0000

Thanks for this skepticism series! As a non-scientist who unfortunately has made it through high school and college with almost no science education, I have a question for you scientists:

Is there any value in collective anecdotal evidence such as product ratings on sites like drugstore.com, makeupalley, and folica? If so, how many individual product ratings need to be averaged for an average rating to be meaningful?

If over 100 people give a product 4 out of 5 stars, I might try it. If over 100 people give it 1 star, I probably wouldn’t buy it. If only a few people rate a product, I ignore the rating. What do you think of this use of anecdotal evidence?

By: Is The Goody Copper Brush Good For Dandruff? | The Beauty Brains

Is The Goody Copper Brush Good For Dandruff? | The Beauty Brains — Sun, 15 Feb 2009 06:02:17 +0000

[...] is plenty of anecdotal evidence that copper brushes are good for dandruff. And there is a scientific evidence that copper ions [...]

By: anactoria

anactoria — Fri, 13 Feb 2009 04:25:46 +0000

What Janis said, totally! I like this series and this part in particular. I still think a lot of this is due, on the US’s part, to the fact that critical reasoning is so absent in American education (and culture, really) and science is so /scary/. I like the way you’re explaining these: simple and to the point. I heard that’s the best way to explain things. ^_~

By: Moxie Hart

Moxie Hart — Fri, 13 Feb 2009 01:36:47 +0000

I’m only really fond of anecdotal evidence/studies when it’s studying something rare enough that you can’t necessarily find enough people with the same experience to create a generalizable sample. They’re interesting for rare diseases/phenomena but even then they’re just a starting point.

By: Janis

Janis — Thu, 12 Feb 2009 17:59:35 +0000

I think the problem with anecdotal evidence is that it’s a starting point, not a conclusion.

If people say, “Pantene seems to make my hair fall out,” that’s where the scientific method STARTS. That’s when you say, “Hm, let’s test this — let’s design an experiment, let’s try to couble-blind it, let’s make sure we have a lot of data points and that we publish so other people can check what we say.” An anecdote is like the key to the car — it turns the crank and gets the whole thing started.

The problem is that people use anecdotes as the endpoint, and not the beginning. Instead of using an anecdote as the beginning of a process to see what’s really happening, they stop there. “Pantene makes my hair fall out, end of story.”

An anecdote is the FIRST brick on the road to knowledge, not the LAST. If you stop there, you never actually get on the road.