When someone is suggests something is scientific fact
The internet is a dangerous place. Each page should come with a warning: "Don't believe what you read on the internet!" Alas, they don't, so it is up to us to navigate the dark recesses of ignorance and polemic on our own.
This is especially true when it comes to science, where every second person is an amateur bio-technologist, wannabe physicist, or fledgling chemist. At best, this means you might be embarrassed at a dinner party when someone responds: "Ahem, I think you might be mistaken. There is no such thing as mermaids". At worst, you may choose not to vaccinate your children, leaving them at the mercy of small pox or polio and endangering others.
Here is a tried and tested primer, call it a bullshit detector, for reading science journalism online (or in print, for that matter):
1. Where are you reading the story?
Certain sites are notorious pedlars of nonsense. Be suspicious of anything with "activist" in the title; it is a blatant sign of bias and shows an agenda at the outset. Do you want to listen to someone with an agenda or someone who is trying to show you different sides of an issue and let you make up your own mind? Same goes for "spiritual", "natural", "earth", etc. I'm not suggesting that you don't read them, but do so with a healthy dose of scepticism. And if the site has "conspiracy theory" in the title and you believe what they tell you without checking it somewhere else, well, then you deserve to be misinformed.
2. Does it make you fear for your life, predict imminent Armageddon, or offer world peace?
If someone tells me the world is about to end, or they have brought out a drug that will cure HIV and Aids (for my sins, I often get family members forwarding me such links), I'm naturally sceptical. Be wary of exaggeration and sensationalism, because it bears the hallmarks of poor reporting and generalisations. As a rule of thumb, if it's salvation or damnation couched in scientific lingo, it's probably wrong.
3. What are the facts, and who is telling them to you?
When someone is suggests something is scientific fact, make sure. First, ask yourself, has this been published in a peer-reviewed scientific journal? The article should source its facts. For example: "High-protein diets linked to cancer, according to research published in the journal Cell Metabolism" is much more believable than "Joe Soap says his amputation was due to excessive use of hair dye". Even then, not all scientific journals are equal. If it's Nature, Science, American Journal of Physics, PloSONE or something in their publication stables, then you can start taking it seriously. It all hinges on peer-review: a process by which scientists' work is subjected to independent review by other scientists in the field. If other scientists in the same field don't believe it, why should you?
4. Who's the scientist?
Science is sprawling and diverse, and increasingly specialised. It is improbable (although not impossible) that one person can know everything about every field of science. Just because someone has a doctorate in physics does not make them a marine biologist. Also, while it may be unfair to play the man and not the ball, what other work has the scientist done? Have they made inaccurate claims before? How was their previous work received?
5. Use common sense
Scientific studies have this aura of certainty about them, the idea that "well, if it was shown in a study, it must be true". Hogwash. How big was the study? Which would you believe: five people saying something, or five thousand? Who performed the study and how did they do it? All of these factors influence whether a study should be taken seriously.
6. This is why we want other people to do the legwork and filter out the nonsense
It is a science journalist's job to ask these questions so that you don't have to. Although we are a rather scarce breed, some local and international publications have science journalists on staff. (Sometimes I've wondered whether this isn't to have a person a few desks away who you can ask really complex scientific questions, expecting an immediate answer – such as: Are GM food going to kill me? When will we live on another planet? Will eating carbs make me fat? Why is my car making this funny sound?) This means that if something major is happening, or about to happen, in the science landscape, reputable newspapers will have reported on it. If you see it on an obscure site, and no one else is writing about it (when it is our job to keep abreast of science news), chances are very high that it's nonsense.
All of that said, don't take anyone's word for it. Not even mine.
Sarah Wild is the Mail & Guardian's science editor