How does the 'crowd' adjust for bias in sources? e.g. if they are all picking the answers to the surveys based on similar methods, e.g. google searches or from listening to the news, how does the crowd avoid the biases from news sources? You can't just 'average them out' if there are systematic skews.

e.g. just because half of the people are watching (say) CNN and the other half are watching (say) Fox News doesn't magically mean that the average of their opinions will be correct. What if both news sources overplayed the likelihood of terrorist attacks? How would the crowd adjust to this?