Carson has been absent from some important party gatherings. For example, Carson did not attend the GOP summit in New Hampshire a couple of weeks ago that featured a huge field — almost every serious (and non-serious) 2016 candidate. Nor did Carson go to Iowa last weekend for a big social conservative gathering that showcased a large number of hopefuls.

As Carson traveled non-politically, he slid down polls of the GOP race. Since the beginning of March, Carson has slipped from 12.3 percent in the RealClearPolitics average of polls — nearly in the top tier of candidates — to less than half that, 5.3 percent, today.

In a new Fox News poll, Carson dropped five points in just three weeks — from being the choice of 11 percent of Republicans surveyed at the end of March to 6 percent in mid-April. It was the biggest drop of any Republican candidate in that period.

In addition to a loss of support, most people still don’t know who Carson is. They don’t know anything good about him, and they don’t know anything bad about him.