Last year, tech analysts from Gartner, IDC, and other firms were roundly ridiculed when they predicted that Microsoft’s Windows Phone OS would surpass Apple’s iPhone by 2016. But this year, IDC is at it again. And as with last year, it stills believe that Windows Phone will outsell the iPhone by 2016.

"Underpinning the smartphone market is the constantly shifting OS landscape," said IDC Senior Research Analyst Ramon Llamas. “Android will maintain leadership throughout our forecast, while others will gain more mobile operator partnerships (Apple) or currently find themselves in the midst of a major transition (BlackBerry and Windows Phone).”

Of all of these mobile platforms, however, it is Windows Phone that will experience the greatest growth over the next four years, at least according to IDC. It will experience an incredible 46.2 compound annual growth rate (CAGR) over the next year to achieve 19.2 percent market share, good for number two, behind Android (52.9 percent market share) but ahead of iPhone (19 percent).

But then that CAGR would pretty much have to be incredible: IDC expects Windows Phone to amount to just 5.2 percent market share this year. Meanwhile, Android is expected to own 61 percent market share in 2012, compared with 20.5 percent for iPhone.

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According to IDC, Windows Phone will be aided by Nokia's strength in key emerging markets. But that number-two position in 2016 comes with a caveat: IDC is assuming that Nokia's foothold in emerging markets is maintained during this time period.

Also worth noting is that, in IDC’s predictions, each of the top three smartphone platforms—Android, Windows Phone, and iPhone—keep selling better each year during the forecasted time period. But overall growth is slowing, particularly for Android and iPhone, both of which will hover around 10 percent growth over the next 4 years. Oddly, the fourth-place also-ran, Research In Motion (RIM) BlackBerry, will achieve 12.1 percent CAGR through 2016, IDC says, and barely cede any market share during this time period: It will end 2016 with roughly the same market share (6 percent) as it has this year.

So what do I think about this? I’ll be happy if Windows Phone achieves north of 5 percent market share this year and 10 percent for the foreseeable future. But beating the iPhone? It’s a bit early to uncork the champagne for that particular celebration.