Rising concerns about cheating on Indiana's standardized tests have prompted the state Department of Education to keep closer tabs on how the test is administered, including evaluating the number of erased answers for clues about whether the results may have been manipulated by teachers.

The number of investigations into testing irregularities increased to 19 this year, according to The Journal Gazette in Fort Wayne. Those include the biggest breach ever of the ISTEP+ test in March, when an eighth-grade essay question was posted on Facebook. More than 80,000 students around the state had their results on that item tossed in a case that involved teachers in three districts.

In other cases, teachers allegedly used live test items to practice with students, created practice problems that matched test questions, taught lessons specifically geared to test questions or told students to change their answers.

Educators say the rising suspicions may reflect a heightened importance for the test scores, which now affect teacher pay, graduation rates and even whether the state will take over failing schools.

"If you can't perform on (the test), you're in trouble, basically," said Stephen Gabet, a newly retired teacher and member of the State Board of Education. "That has unfortunately put pressure on people."

Local districts usually investigate cheating allegations and handle punishment. But Gabet said the education board recently gave the department permission to create rules on testing security.

"The test means so much now that we are watching a little more closely," said Wes Bruce, the state's chief assessment officer.

A growing concern is the number of erasures in which an answer is switched from wrong to right. Such incidents have been problematic in districts across the country, including in Washington, D.C.

Erasures are defined as graphite appearing on more than one testing bubble. They don't always indicate cheating — in some cases, a student may have lightly crossed out wrong answers to eliminate them or misnumbered the answer sheet. Scanners pick up the remaining graphite.

But an analysis of Indiana's state's 2009-10 ISTEP+ tests showed almost 4 percent of the state's schools were flagged for having at least one classroom with an excessive number of answers that were changed from wrong to right.

Those included a third-grade English/language arts class in which 23 students out of 25 accounted for 126 erasures. Of those, 104 were answers changed from wrong to right.

In another case, all 20 students in a third-grade math class had at least one erasure. All but four of the 125 erasures changed answers from wrong to right.

Nate Schnellenberger, president of the Indiana State Teachers Association, acknowledged that teachers are feeling more pressure to perform. But he said that doesn't translate into "widespread cheating."

Bruce agreed that most Indiana schools were well within statistical boundaries and cautioned against jumping to conclusions.

"My concerns are it's statistical and not clear-cut," he said. "We didn't want to be on a witch hunt. We don't know that that teacher actually cheated."

He said about 90 of the state's 2,400 schools were sent informational notices about questionable classes.

Steven Yager, superintendent of Southwest Allen County Schools, said one of Southwest's best teachers was flagged for having high erasures. An internal analysis showed the teacher regularly prompted children to use extra time to review answers and that the principal proctored with that teacher the day of the test.

Though that teacher wasn't involved in cheating, Yager said the erasure analysis is probably beneficial.

"When teachers know it's a possibility, they will toe the line," Yager said. "Maybe we should have been doing this all along."