Evacuees in area schools being held back at high ratesOne in four Houston Independent School District students displaced by Hurricane Katrina failed to make enough academic progress to be promoted to the next grade this school year — a far higher rate than their classmates and an indicator of the massive challenges still facing area schools. About 700 of the 2,900 Katrina students returning to HISD this year were held back, including 41 percent of high school sophomores and 52 percent of juniors. That 24 percent retention rate was among the highest in the area, according to retention rates released...