Dallas ? Dozens of Texas schools appear to have cheated on the state’s redesigned academic achievement test, casting doubt on whether the accountability system can reliably measure how schools are performing, the Dallas Morning News reported.

An analysis uncovered strong evidence of organized, educator-led cheating on the Texas Assessment of Knowledge and Skills at schools in Houston and Dallas, along with suspicious scores in hundreds of other schools.

Texas education policies on student accountability became the model for the federal No Child Left Behind Act.

The newspaper analyzed scores from 7,700 Texas schools, searching for ones with unusual gaps in performance between grades or subjects.

More than 200 schools had large, unexplained score gaps between grades or between the TAKS and other standardized tests, such as the Stanford Achievement Test.