Many Katrina refugees who were unceremoniously dumped in Plano just stayed. Once they relocated and realized they could live in a safe city with excellent schools, they didn't want to go back to New Orleans. One family had 4 boys, ages 13 to 6 when they evacuated here from the 9th Ward. The 13-year-old could not read or write, but he did manage, after getting a ton of remedial help, to graduate from Plano Senior High. The next brother did a little better. The twins, who were 6 when Katrina hit, were taking 9th grade algebra I as 8th graders and set to take AP classes in high school (they just graduated and are in college now.) New Orleans has certainly failed its citizens for too long. The education system is an embarrassment that school districts all over found out about when the Katrina Kids entered new schools.
The New Orleans public school system thankfully has undergone a dramatic overhaul since the storm. A couple really good friends are married teachers in Mississippi and they speak of the age problem and literacy problem. It was eye-opening. I believe it is a socio-economic issue.