FORTUNE — The NPD Group’s Stephen Baker chose Tuesday 9/11 — the day before the expected launch of Apple’s (AAPL) new iPhone — to pour cold water on what he calls the “growing expectation that this release will achieve the equivalent blowout sales success that the iPhone 4s enjoyed.”
Equivalent? As we reported Monday, conventional wisdom on Wall Street has it that the iPhone 5 will outsell the iPhone 4S by a wide margin.
Among the handful of analysts who were willing to venture a guess, estimates for iPhone 5 sales this quarter (i.e. in the eight days from 9/21 and 9/29) ranged from 6 to 12 million. It took Apple three days to sell 4 million iPhone 4S units last year. Topeka’s Brian White estimates by day 3, the company will have sold 5 to 5.5 million iPhone 5s.
Stephen Baker begs to differ.
Baker may be right. But it’s also true that the NPD group measures only U.S. retail sales, while Apple sells all over the world. In fact, of the 37 million iPhones it sold in the December quarter last year — the first that included the iPhone 4S — nearly half (17 million) were purchased outside the U.S.
All this suggests that the number to watch for at Apple’s special event tomorrow is how many countries will be getting the new phone on Day 1. Last year, the iPhone 4S launched initially in the U.S., Australia, Canada, France, Germany, Japan and the U.K..