The Associated Press has an article on how the demographics of New Orleans changed post-Katrina:
Those who have moved back to New Orleans in the three years since
Hurricane Katrina devastated the city are likely to have higher incomes
and more education than people who haven't come back, demographic data
New Orleans remains predominantly black, as it was before Hurricane
Katrina struck in 2005, U.S. Census Bureau figures show. But people who
have some college education, are above the poverty line, own homes
and have no children are more likely to have returned to the city than
others, says William Frey, a demographer at the Brookings Institution
The city was 59 percent black in 2006, the most recent census
figures available, compared with 68 percent in 2005. Census data shows
20.6 percent of New Orleans residents were below the poverty level last
year, compared with 24.5 percent in 2005.
OK, the fact that the demographics of New Orleans have changed coincident with the Katrina evacuation is a fact. It is based on probably the best demographic data available, though it is not clear that Mr. Frey has the evidence at hand to separate the effects of economic growth in New Orleans from migration patterns in explaining the drop in people below the poverty line, but I will cut him some slack compare to this next statement:
"The people who have come back are the people with the best resources
to come back," said Frey, a demographer at the Brookings Institution in
Washington who has studied the demographics of New Orleans. "The people
who have not come back are lower-income, minorities, largely renters.
They were the least equipped to come back and have not been able to."
This is a guess. The data Mr. Frey is working with sheds no light on the reason certain groups did not return. His statement that they did not come back because they did have the resources to do so is an unproven hypothesis. I could easily offer a counter-hypothesis, that the issue was that these folks did not have the resources or the knowledge to leave New Orleans to find opportunities to escape their poverty, and having been granted the unique opportunity by the Katrina evacuation to get out, they have found opportunity elsewhere and see no reason to return to the place where they were formerly impoverished. I actually think my hypothesis is more likely than Mr. Frey's, but in the end both of us are guessing.