"Technical difficulties" caused computerized testing in Colorado to "not operate optimally" for several hours Tuesday morning, according to the Colorado Department of Education.
The window for new, required science and social studies testing developed by the state opened Monday for Colorado's 179 public school districts.
The CDE told schools to not start or resume additional sessions of the Colorado Measures of Academic Success testing after the problem started, said Cami Anthony of the communications division.
Anthony said students who had begun testing sessions could continue.
The malfunction, she said, was believed to be a server issue on the part of Pearson State Assessment Services, the for-profit test administrator for Colorado.
In a statement emailed Tuesday evening, a spokeswoman for Pearson said the "unexpected service interruption prevented some test administrators from logging in to PearsonAccess," which is where test sessions begin. She said those logged in before the interruption were not affected.
Problems started at 9:45 a.m. and were fixed about 2 1/2 hours later, Anthony said.
At the time, 34,396 students of the 62,000 testing on Tuesday were taking the test, Anthony said.
The state does not know which school districts were impacted, said Janelle Albertson Asmus, chief communications officer for the CDE. But, she said, "more than 30,000 students were able to test even as the technical glitch was being solved."
Some schools related a different experience. A Colorado Springs School District 11 teacher said halfway into the testing, "the whole thing just shut down."
"It was like crash and burn," he said.
District 11 spokeswoman Devra Ashby said schools reported various problems.
While some students were kicked out of the system and some could not complete the test, she said others experienced difficulties with graphic-intense videos or had trouble dragging and dropping items on the computer screen.
Asmus said "functionality challenges," such as the drag-and-drop function not working properly, would not have been related to the morning's technical difficulties.
Students in fifth and eighth grades are taking new science assessments, and students in fourth and seventh grades are doing social studies tests online, based on new academic standards.
About 46,800 students tested on Monday, the first day of the window.
Schools set their own testing schedule, and many divide the sessions into multiple days. The testing period for the science and social studies portions closes May 1.
Schools normally switch to shortened class periods to accommodate the testing schedule.
"Students had to return to their classroom, when teachers might have had a 20-minute presentation planned and instead had to extend their materials to 50-minutes plus," said the D-11 teacher, who asked not to be identified.
"It's basically like someone giving you a 5-minute warning to turn your presentation into an hour-long run and have your job still based on performance," he said.
The glitch occurred at a time when state lawmakers are debating several bills to reduce standardized testing and change the requirements.
During other testing last month, District 11 had to postpone a day of testing after its computers were attacked, causing computers districtwide to shut down. No data was compromised, officials said.
The state is paying Pearson about $27.5 million to provide vendor services for the state's science and social studies tests, as well as new English language arts and math tests developed by a multistate consortium that includes Colorado.
Students took the latter primarily before spring break.