I don't :)

If there is a disagreement on, say, the status of Taiwan, even someone who doesn't know much it might agree that some good predictors would agree that some good predictors would be "knowledge of the history of Taiwan", "Having lived in Taiwan", "Familiarity with Chinese culture", etc.

And it can be interesting to see whether:

• People of different opinions consider different predictors as important (conveniently, those that favor their position)

• Everyone agrees on which predictors are important, but those who score highly on those predictors have a different opinion from those that score lowly (which would be evidence that they are probably right)

• Everyone agrees on which predictors are important, but even among those who score highly on those predictors, opinions are split.

I guess what I'm getting at is "If you take the outside view, how likely is it that your opinions are true"?

How do you propose to determine what constitutes a 'correct' opinion on any given controversial issue?

The only way that makes any sense, see how closely they match her own! :)