Computer glitches that plagued thousands of students taking state standardized tests last spring had no impact on scores, according to a report authorized by the Minnesota Department of Education.

Many state educators had worried that the computer problems would lower students’ scores on the Minnesota Comprehensive Assessments, high-stakes tests that influence federal poverty aid for schools and teacher merit pay.

But in a letter sent to parents and superintendents this week, Education Commissioner Brenda Cassellius said an analysis by a Virginia firm shows no reason for lingering concerns. Test scores are scheduled to be released Tuesday.

“I want to emphasize that although the report suggests the technical difficulties did not lead to widespread or significant effects on statewide student and school scores, there is no doubt that a number of Minnesota students were affected by those days,” Cassellius wrote. “However, because of your leadership and extraordinary dedication and hard work of students, teachers, parents and administrators, the impact of those disruptions were minimized.”

Not all school leaders are convinced the problems didn’t influence students, however.

“When I look at these test results and other results, it’s clear they had an impact,” Minnetonka Superintendent Dennis Peterson said.

Others accepted the conclusions in the report, which was also reviewed by a panel of technology and policy experts in Minnesota.

“We believe [the computer problems] have had no impact on our scores whatsoever,” said Rick Kaufman, a spokesman for the Bloomington public schools.

Most of the computer malfunctions occurred on April 16 and April 23. Some students encountered delays logging on, while others were forced to end their sessions early. The department estimated that 15,000 students from 400 schools were affected by the problems over the two days.

The state Department of Education temporarily suspended testing on April 16 and gave students more time to complete the exams — a decision backed by the U.S. Department of Education, which was also monitoring online-testing problems in Indiana, Kentucky and Oklahoma.

Vendor, state continue work

Officials with American Institutes for Research (AIR), the department’s testing vendor, said Internet problems caused the glitches one day, while a database server malfunctioned on another.

Jon Cohen, AIR’s executive vice president, said the online tests were designed to compensate for disruptions and he wasn’t surprised that the analysis showed test scores weren’t compromised.

“We are constantly improving our protocols,” he said. “We are constantly improving our testing.”

In Cassellius’ letter, she tells parents she will continue to work with AIR to make sure there are no future problems. AIR’s $61 million contract with Minnesota expires in 2014.

The Star Tribune obtained copies of hundreds of messages sent to the department that show schools’ increasing frustration with AIR’s help desk before and during the testing period.

“I’ve dealt with the AIR help desk a couple of times, and I would not characterize any of my interactions as satisfactory,” wrote a testing supervisor at the Forest Lake School District. “Usually it takes a followup to get an answer to the question originally posed, rather than a pre-written answer. They don’t do better than I would expect a pretty poor ... artificial-intelligence system would do.”

During the 2011-12 school year, Minnesota had no significant issues with the online MCAs administered by AIR.

Last year, however, more schools opted for online instead of paper tests. All science tests are taken online, and about 95 percent of students took the math tests online. Of reading test-takers, about 30 percent of students completed them online.

Test scores have influence

The MCAs influence the state’s current school-rating system, which requires chronically underperforming schools to make improvements. Test scores also factor into Q Comp, Minnesota’s merit-pay system for teachers, and federal poverty aid for schools.

Cassellius sent a letter to parents earlier this summer warning them they may see a drop in reading scores on the MCAs as a result of the state’s adoption of Common Core standards, a rigorous set of national teaching standards.