[thingylab]

Any practical reason you'd want a "non brand related" index? The way I understand it the Big Mac index is pretty good because it casts a wide net from the cost of producing (or importing) food to the price of labour, and everything in between. I doubt you'd get that with a potato.

[Drakim]

While it's true that the price of labor, production, transportation, etc, would affect the cost of the Big Mac, it's still ultimately up to McDonalds to set the price, deciding what sort of margin they want from the product, maybe taking into account stuff like brand recognition.

So, using something like the potato would eliminate that sort of "bias" to the product, as no one party controls the potato, and thus couldn't artificially set the price higher at a whim. If the price of the potato rose, it would be because the whole market reacted to some changes to transportation or production costs, not because management has decided that they want to build their brand as being expensive and exclusive (which we know happens with a lot of brand products).

[thingylab]

1) I think you're asking too much of what is essentially a silly experiment.

2) What if potatoes become hip?

3) If you want auditable PPP conversion rates: http://data.worldbank.org/indicator/PA.NUS.PPP

[jsprogrammer]

There are dozens of varieties of potato. Not all have the same costs to go from seed to market.

What is a 'potato'?