Do 9 out of 10 dentists really recommend that toothpaste Am I Normal with Mona Chalabi
Transcriber:
When it comes to toothpaste commercials,
you’ve probably heard claims like,
nine out of 10 dentists
recommend “Brighter, Whiter.”
Or maybe it’s four
out of five or 80 percent.
But either way, these companies expect
you to see a wall of white coats,
trust their authority
and think no further.
Now that approach is basically BS,
and you probably know it’s BS,
but the question is:
How can you trust your BS radar?
[Am I Normal? with Mona Chalabi]
Well, when I’m faced
with suspicious statistics,
I tend to ask myself three questions.
First, what were people actually asked?
Sometimes the question
that is put to survey respondents
is wildly different than the one
that ends up on posters and billboards.
For instance, in 2007,
one toothpaste ad in the UK
claimed that more than 80 percent
of dentists recommended their products.
What that sounds like
is that a majority of dentists prefer
their product over all others,
that those dentists were asked
if this was the best product.
But when the Advertising Standards
Authority looked into it,
they discovered that the dentists were
asked to recommend several toothpastes,
not one single choice.
In fact, another brand
was found to be almost as popular.
To no one’s surprise,
the ad was deemed misleading.
Now, the second question to ask is:
What aren’t you telling me?
In the 1970s, a sugarless gum company
claimed that four out five dentists
recommended their product.
Now, their slogan was pretty upfront
about the fact that these dentists
were only recommending the product
to people who already chewed gum,
but they weren’t so forthcoming
about the fifth dentist.
Decades later, the manufacturer
made fun of it in a new ad campaign
where they blamed the fifth
dentist’s different thinking
on a freak accident,
like a sudden squirrel bite.
Now, since I’m all about
the deviations in the data,
I decided to look into this
a little bit further.
In fact, it’s not that the fifth dentist
recommended chewing sugary gum.
What they don’t say
is that most of them recommended
that their patients don’t chew gum at all.
The last thing to ask is:
What was the survey context?
Because there’s a really big difference
between saying “nine
out of 10 dentists agree,”
and “nine out of these 10 dentists agree.”
Size matters and so does methodology.
According to the American
Dental Association,
there are about 200,000
registered dentists in the US.
I’m not going to bore you
with the maths here,
but to get a statistically significant
sample of 200,000 people,
you need about 400.
So if you’re reading in the fine print
that only 50 dentists were surveyed,
you know that’s not
statistically significant.
It’s just a marketing ploy.
So the next time you see one of these ads,
ask yourself:
What were people actually asked?
What’s gone unsaid?
And what was the survey context?
Hopefully, with those three questions
and a little bit of skepticism,
you will be able to understand
when the data is legit
and when it’s irrelevant.
Nine out of 10 Monas agree.
[*No such survey
took place]