The news this morning is that Rick Perry, after going back to Texas to reassess his candidacy, is...staying in? That's what's apparently happening, according to multiple sources. I suppose it might even be true. On the other hand...no one says they're out until they're really out, and plenty of campaigns have pulled more sudden u-turns: I wouldn't be at all surprised if this reprieve lasts only 24 or 48 hours.
Why would a campaign do that? Well, if they really are trying to calculate their chances, then they would want potential donors and current supporters to believe that they're still in, for now. Drop this out there, and see if any money comes in over the next day or two. See, too, what their high-visibility supporters tell them. Until you're absolutely certain that you're dropping out, there's no reason to even hint at it. So they might just be making one last bluff.
And even if Perry and his staff believe they're going to stay in, that's still no guarantee that they'll still believe that after a couple of days.
So I only know what I read, but I just wouldn't take claims that he's staying in at face value.