Claims of a cure for cancer? Ask For Evidence

Did you hear the claim that sleeping naked can cut your risk of diabetes? Or have you read the advert on your Facebook page extolling the virtues of some new 'miracle cure'? What about the ads on the bus selling a 'superfood' supplement giving you more energy to face the day?

Did you believe them? Did you take their word for it?

These topics are too important for us to take on trust. If you've heard a politician, public figure, NGO or an advertising campaign make a claim then you are entitled to ask: Is that really true? And you don't have to be an expert in the field to ask for evidence behind a claim. If you're interested, that's enough.

It's easy to ask

Launched earlier this month, Sense About Science's Ask for Evidence website means it's easy to ask, and get help understanding the reply. And if you don't get anything back, it's all public so we can help put the pressure on those naughty non-responders.

The site also tracks requests for information, logs responses received and includes a discussion section for experts to join in. It also offers tips on how to judge any evidence you do receive. Cancer Research UK, for example, is on hand to help judge any evidence about cancer prevention treatments – and there are useful links like its 'cancer controversies' page – a one-stop myth-busting shop.

The great thing about the campaign is that with more people asking for evidence, the more politicians will realise they should check the facts before announcing a new policy; more companies will be straight with their consumers; and more journalists will provide data for their claims.

Soon we will be able to see who can provide evidence for their claims and who ends up doing an embarrassing back-pedal.

A good stack of evidence

Last year I asked Boris Johnson for evidence behind his claim that using biodiesel made from London's used cooking oil in London buses could save 50,000 tonnes of carbon dioxide a year. It was Transport for London who provided the evidence. The team took me through its calculations and showed me the reports that produced the numbers. It was reassuring to see that there was a good stack of evidence to back up Johnson's claims.

But it's worth remembering – never assume that someone, somewhere, has looked at the evidence before deciding what's good for you or what's good for selling a product.

Always ask for evidence.