Griffin might have made the same mistake no matter what, but generally the more ideologically diverse an organization the more likely it is that mistakes will be caught. Take the Dan Rather memogate story. It would not have required a rocket scientist to catch the myriad problems with that story. Indeed, all it would have taken is someone in the room who was not only skeptical, but who actually did not want the story to be true and so was keen to find flaws with it.
Having someone that disagrees with your ideas and challenges you on it forces you to defend your ideas.
It seems to me that scientists understand this problem very well, which is why they have such stringent rules to confirm their findings. Everybody wants to find a cure for cancer. Everybody wants their theory to be proven right. So, scientists send their work out to other scientists who may be just as eager to find a cure for cancer, but not nearly so eager that their competition finds it first. So those peers work very hard to find the weak spots in the theory. Mistakes still make it through, but the error rate in scientific studies (which is remarkably high, I'm told) is still much, much, lower than what we find in New York Times as a matter of course.
Peer review is a way to have rivals look over your work.
Another way to reduce bias is the doubleblind experiment. This is where the work is divided. One group designs the experiment, another, seperate one, conducts it, and yet another analyzes the results.
Now that's a bit more rigor than the media has the time for, but they shoudl at least have something.
But as previous posts have shown, the media isn't interested in selling the best news. They want to help get a politician in that will ensure their existance.