ATLANTA (AP) - Teachers spent nights huddled in a back room, erasing wrong answers on students' test sheets and filling in the correct bubbles. At another school, struggling students were seated next to higher-performing classmates so they could copy answers.

Those and other confessions are contained in a new state report that reveals how far some Atlanta public schools went to raise test scores in the nation's largest-ever cheating scandal. Investigators concluded that nearly half the city's schools allowed the cheating to go unchecked for as long as a decade, beginning in 2001.

Administrators - pressured to maintain high scores under the federal No Child Left Behind law - punished or fired those who reported anything amiss and created a culture of "fear, intimidation and retaliation," according to the report released earlier this month, two years after officials noticed a suspicious spike in some scores.

The report names 178 teachers and principals, and 82 of those confessed. Tens of thousands of children at the 44 schools, most in the city's poorest neighborhoods, were allowed to advance to higher grades, even though they didn't know basic concepts.

For teachers and their bosses, the stakes were high: Schools that perform poorly and fail to meet certain benchmarks under the federal law can face sharp sanctions.

They may be forced to offer extra tutoring, allow parents to transfer children to better schools, or fire teachers and administrators who don't pass muster.

Experts say the cheating scandal - which involved more schools and teachers than any other in U.S. history - has led to soul-searching among other urban districts facing cheating investigations and those that have seen a rapid rise in test scores.

In Georgia, teachers complained to investigators that some students arrived at middle school reading at a first-grade level. But, they said, principals insisted those students had to pass their standardized tests. Teachers were either ordered to cheat or pressured by administrators until they felt they had no choice, authorities said.

One principal forced a teacher to crawl under a desk during a faculty meeting because her test scores were low. Another principal told teachers that "Walmart is hiring" and "the door swings both ways," the report said.

Another principal told a teacher on her first day that the school did whatever was necessary to meet testing benchmarks, even if that meant "breaking the rules."

Teachers from the investigation contacted by The Associated Press did not return calls or declined to comment.

Educators named in the investigation could face criminal charges ranging from tampering with state documents to lying to investigators. And many could lose their teaching licenses.