>Recently when returning to Europe, after the start of the Ukraine war (+ inflation) a lot of my friends asked if food prices had also went up in Japan. I said yes but not as much as Europe. Price of wheat surely went up but everyone eats rice there, so except for bakeries (not many of them) most people didn't feel much.
While it's true that europeans/americans eat wheat and asians eat rice, it's at best an incomplete explanation for why inflation was lower in japan than in the US. In the BLS CPI basket, "Cereals and bakery products" (not just wheat) only make up about 1/8th of the food category. The cost of flour is going to be a further fraction of that.
>The legitimacy of an academic/scientific field can be somewhat roughly measured by how rigorous their measurement instruments and units are, and the conclusions the scientist try to make out of it.
I'm not sure what you're trying to get at here. Are you trying to imply economics isn't rigorous? All the indices you mentioned are at best, are used informally. The world bank or the federal reserve isn't trying to measure inflation using big macs, for instance.