In international trade we could invoke the "small country" assumption without worry:
Analyzing 36 years of gasoline prices and U.S. oil production, the Associated Press finds no statistical correlation between how much is pumped out of the ground and how much is paid at the pump.
AP says four independent statisticians came to the same conclusion. ...
When U.S. production goes up, the price of gas "is certainly not going down," said New York University statistics professor Edward Melnick. "The data does not suggest that whatsoever."
AP's statistical analysis examined monthly, inflation-adjusted prices and production from the Energy Department stretching back to January 1976, when they were first recorded. AP then turned over its analysis to Melnick and three others -- Phil Hanser, an economist and statistician at the energy consulting firm the Brattle Group; University of South Carolina statistics professor John Grego; and David Peterson, a retired Duke University statistics professor.
AP writes that the four "looked at the analysis, ran their own calculations, including several complicated formulas, and came to the same conclusion."
The change in supply from additional U.S. drilling is so small compared to the rest of the world's production that the supply shift has no effect on prices.
