A consensus of opinions is not as worthy as a consensus of the evidence.
Not unless you’re a politician of the kind that only cares for what they can ride on the public with and doesn’t give a toss about what is correct.
That’s not to say that there are things outside of science that matter for some policies, just that the two types of consensus are not the same and when evidence matters, opinions cannot be considered more worthy.
bioemphemera has an excellent post on this topic. Among other things, she points out that wikipedia entries and blogs can be–if done poorly–an indirect form of consensus.
Saying X million people believe in <<choose your topic>> says nothing about if it is right or not.
For the same reason, we all know (or should realise) that TV and internet polls are largely useless…
…unless the audience has deep knowledge of the evidence for the subject in question, it’s merits and weaknesses, and is honestly presenting what can be concluded from that evidence, not “opinion”.
Note that last one: they have to not be presenting opinion.
You might like to think that wikipedia entries and blog articles are better, but try reading around on something you know from evidence (not opinion) and you’d find it’s not always true, so if you’re reading something you’re not an expert on you’re stuck with trying to work out if they’ve got it right.
I’ve always said that while wikipedia can (sometimes) be a good starting point, it’s a lousy end point.
You need to take the claims made and track them back to the original sources and verify them. And check what’s been left out. They do give sources for at least some of their claims, which helps, but someone has check them and speak up…
As a simple example when writing about tinnitus, I noted a claim that Joan D’Arc suffered tinnitus as if that were a fact. I couldn’t see how that could be verified (if it can’t it shouldn’t be presented as a fact), nor that it was likely from the description given. A quick check confirmed my suspicion; while possible, it can’t be verified and seems more likely to be a case of garnering famous names and sloppy (over-zealous?) writing.
One difference is the knowledge of those who make the wikipedia entries or write the blogs posts and the extent to which what they write, or say, reflects what evidence-based studies show.
What constrains the words of experts speaking in public are their peers. In speaking in public they represent their community, the science community. The scientific community holds a very harsh view of the those who speak nonsense.
Get out of line too often and you’ll find your career looking shaky.
In essence, their membership of this (very!) judgemental community is their assurance that their word will be fair attempt to get it right.
It’s not that scientists can’t oppose current ideas, that’s done all the time, and when it’s done, it’s done by presenting evidence for alternative positions amongst peers who are familiar with the evidence.
So what of blogs?
Bloggers can write whatever they like… if nothing constrains them.
Qualified scientists blogging tend to write cautiously, partly because of the harsh views that the scientific community holds of people that talk rubbish. You’re very unlikely to see out-and-out nonsense put out by a scientist, from the peer pressure alone never mind any other factors.
There’s also that scientists tend to constantly ask themselves “do I really know that?” when they are writing an article. It tends to become ingrained after so many years.
It’s particularly straight-forward in blogs for errors to be corrected. Anyone can speak up and correct what written and the correction will go down for the record against the writer’s own words; no-one who values being correct wants that!
A habit of citing original sources helps, too. That way readers can just go and check for themselves.
There is no universal formal oath that we, as scientists, are bound to speak accurately on matters that we are experts, but the training and community pressure work to that effect regardless.
Other science journalism posts in Code for life: