ATLANTA -- Democrats called today for an investigation into the dismal state test results that sparked an uproar among parents and could force thousands of students into summer school.

The House Democratic leadership and party Chairwoman Jane Kidd demanded Gov. Sonny Perdue appoint an independent investigator to find out when State Schools Superintendent Kathy Cox knew students would fare poorly on the test and what could have been done to prevent the confusion and controversy that followed.

"Clearly, the system has failed our students and our teachers," said House Minority Leader DuBose Porter, D-Dublin, a potential gubernatorial candidate in 2010. "We want to get to the bottom of what caused this problem. Our teachers and parents deserve answers, and the students deserve really true reform."

Almost 40 percent of Georgia eighth-graders failed the state's math test, which students are required to pass to advance to high school. Between 70 and 80 percent of sixth- and seventh-graders failed the social studies exam.

State Schools Superintendent Kathy Cox later vacated the social studies results but stood by the math test, saying the higher failure rate was to be expected as the state moves to a new, more rigorous curriculum.

The Department of Education has also set aside $1.4 million to help schools deal with a potential flood of unexpected summer school students studying for a chance to retake the test, but Democrats say that's not enough.