I had heard that there was an argument over the price of crude oil: Was the price of crude oil going up due to the fall of the US Dollar (meaning, the price of oil was remaining stable in other currencies) or was the price of crude oil prices just going up, regardless of the currency?
I did a quick-and-dirty analysis and found that the answer is a little bit of both. For my analysis, spot oil prices came from the Energy Information Administration (EIA), the statistics division for the U.S. Dept. of Energy; historical exchange rate data I got from Exchange-Rates.org. From there it was a simple matter of taking the EIA data and converting it from U.S. Dollars into Euros. To make matters simpler, I have used data from a very limited length of time, from January 1 through March 11, 2008, a little over two months.
As you can see in the two graphs below (both of which I created on Excel), the spot prices for both West Texas Intermediate (WTI) and Brent Oil in US Dollars and Euros are very tightly bound from January 1st through February 26th (point 38 on both graphs). Up through this point, the correlation coefficient is 0.986 and 0.982, respectively. (A correlation coefficient of 1 means a perfect positive correlation; this is an extremely strong correlation we're talking here.) Then on February 27th, there's a break between the two currencies. The price of oil in Dollars goes down slightly, but the price of oil in Euros goes down much more (for both WTI and Brent). Even though the correlation coefficients get even tighter during this period (February 27 through March 11) - 0.994 and 0.992, respectively - you can see there's an obvious gap between the spot prices for both markets in the two currencies. The price of WTI oil in Dollars has grown by 9.12% since January 1, whereas it's only grown by 4.92% in Euros. (For Brent Oil, the growth rates are 10.1% and 5.8% in Dollars and Euros, respectively.) But this difference only really started back on February 27th.
So, now that I've gone all technical on ya, how can I explain this in simpler terms? It's as if two ice skaters were skating together very tightly. From January 1st through February 26th, they're dancing more or less cheek-to-cheek every day. Then on February 27th, the two skaters decide to let go of each other. They're both doing the same moves (even better than before), but now they're moving further and further apart. In that regard, the answer is both: crude oil prices are moving up and it doesn't really matter what currency the price is in. However, that one day, February 27th, the change in the exchange rates has caused the price of crude oil in Dollars to go up by about twice the amount in Euros.
Update: Cross-posted at Daily Kos.