[splat]

It's more a by-product of the fact that the Kepler mission has produced so many planet candidates (with an estimated ~50% false positive rate) that it would require about 30 years of telescope time on the world's largest telescopes to actually confirm that the stars have planets.

[danking00]

Can you cite a source for your 50% false positive rate? I found a source[1] that argues for a ten percent false positive rate.

What do you mean to "confirm" that the stars have planets? I could imagine, directly imaging them is confirmation, but, as I understand it, that's nearly impossible for the average exoplanet we've found. What types of data are Kepler and COROT lacking which you desire for confirmation?

[1] http://arxiv.org/abs/1101.5630

[splat]

The false positive rate seems to have been revised to 40% since I last checked, but my reference is here (though they cite the Morton & Johnson paper, too):

http://adsabs.harvard.edu/abs/2011ApJ...736...19B

The 10% false positive rate is for rank 2 targets, but the majority of targets are rank 4, which have a 40% false positive rate. (See section 2.2.2)

To confirm that the stars have planets, one would do spectroscopic follow up. You would see the slight wobbling of the host star due to the gravitational influence of the planet, and this would manifest itself in a slight Doppler shifting of the spectral lines of the host star. The problem is that most of the stars that Kepler is observing are so faint that ground-based spectroscopic follow-up is impossible except on the largest telescopes, and even then you can only do it for a handful of the thousands of candidates that Kepler is discovering.