A: Lots of ways. But one very important way would be to use information about where prices are very high. That would tell me that (1.) people really want the stuff there, and (2.) it is costly for suppliers to get the stuff there.
You want to know other things too, of course (this indicator is censored, after all). But freely fluctuating prices seem to communicate a lot of the information you'd need.
A dull-witted sensor?
10 hours ago