Let’s say your friend B tells you that they’ve been drinking this amazing tea and have lost some weight as a result. The tea is endorsed by a celebrity your friend really likes, say, Ms. Famous Actress. It’s also quite expensive.
It just so happens to be a time when you’d also like to lose some weight. This tea sounds really good. Should you run to the store and get some for yourself ASAP?
If you apply a bit of skeptical thinking – no, not really. Not yet, anyway.
After all, there’s so little information to go by in B’s story. And you can use a fairly simple set of questions to establish more trustworthy information. It’s not that your friend is trying to mislead you, but it’s also possible that the tea really is too good to be true.
Firstly, it’s not good enough if B is just claiming to have lost a couple of kilograms. There needs to be evidence of this. It’s not because you think your friend is lying about it, but independent confirmation of facts is always necessary.1
Secondly, ask yourself how the endorsement from Famous Actress is important. Is she a world-renowned expert on weight loss teas? Likely not – hence her authority is irrelevant here.
Thirdly, is there anything else your friend was doing differently while drinking this tea? For example, exercising more, or cutting out certain foods? After all, the hypothesis here is that the tea specifically is causing weight loss. To be able to test that hypothesis, you need to start by looking at possible confounding factors and see whether any of those are more likely.
Fourthly – what’s in this tea, anyway? Exotic ingredients you’ve never heard of, or a mixture of herbs you could pick in your back garden? Are any of the components known for their weight loss properties and, most importantly – have they been experimentally tested?
That’s just the most basic toolkit2 of questions to get you started, but it can make a huge difference in your final decision. After all, the tea is really expensive, and you don’t want to waste all that money on something that may not work.
Of course, you would not conduct a scientific test yourself – but it’s good to at least know what standards you’re after.
Tomorrow – on proof via scientific experiments.
This is skeptical week. To find out why it’s skeptical week, please read Monday’s post.