Is Android Really Outselling Apple?

Here’s a curveball of a data point: Android is now outselling the iPhone.

Really? Really, says NPD.

The consumer research shop says U.S. sales of smartphones using Google’s mobile operating system climbed past Apple in the first three months of this year. Google (GOOG) nabbed 28 percent of the market, while Apple (AAPL) claimed 21 percent, NPD says. Less surprising is that BlackBerry maker Research in Motion (RIMM) still leads the market, with 36 percent.

Here are the data in chart form: Android is the green line with the prominent spike:

NPD’s numbers come from self-reported online consumer surveys (corporate sales aren’t included), so there’s likely some variance between its results and actual sales data. And indeed, NPD’s numbers look quite different from the most recent numbers from comScore (SCOR), which showed Google with a 10 percent share in February.* Still, NPD is usually considered a reasonably accurate estimator of retail sales, so the report is worth taking seriously.

The best argument in support of NPD’s numbers, meanwhile, is that Google’s handset and carrier partners, particularly Verizon Wireless (VZ) and Motorola (MOT), have been pushing their Android phones hard in recent months. And perhaps potential iPhone buyers are in a wait-and-see mode until June, when Apple is expected to unveil a next-generation handset. But this explanation requires an awful lot of iPhone buyers to be awfully savvy about Apple’s product cycle.

Anyway, this isn’t necessarily terrible news for Apple, as the company faces a possible federal antitrust probe. The NPD number is certainly more humble than the data Steve Jobs was boasting about last month when he noted that the iPhone had 64 percent of the mobile browser market.

*Important distinction between the NPD and Comscore data: NPD is measuring sales, and Comscore is measuring installed base. So entirely possible for those two data sets to sync up. More in Digits.