Updated 5/5: Late last week the Houston Chronicle reported that the Children at Risk findings used flawed statistical analysis.
"The mistake involved a 'growth index' as part of each school's ranking. The measure of how much individual students improved on state exams in reading and math from 2012 to 2013 was based on an inaccurate formula. Some results may have been off by decimal places while others had a bigger variation.
This week the nonprofit group Children at Risk released their annual school rankings, which look at the Texas Education Agency to rank 7,000 schools. By their own admission, Children at Risk's analysis has its flaws.
"The limitations posed by TEA data are valid criticisms for the school ranking system. Any erroneous data reported to or by TEA may have an effect on the rankings," the group said in a statement accompanying the rankings.
So what does that mean? Take it all with a grain of salt. Here are the 10 worst schools that all received an F letter grade, according to Children at Risk.