CHICAGO -- To motivate juniors for last April's assessment exams, Springfield High School offered coveted lockers, parking spaces near the door, and free prom tickets as incentives for good scores.
But the incentives at the central Illinois school went unclaimed until earlier this month, when Illinois finally published its 2006 test scores -- more than four months after they were due.
Critics pounced on Harcourt Assessment Inc., which lost most of its $44.5 million state contract over delays -- caused by everything from shipping problems to missing test pages and scoring errors -- that made Illinois the last state in the nation to release scores used to judge schools under the federal No Child Left Behind Act.
But specialists say the problems are more widespread and are likely to get worse.
A handful of companies create, print, and score most tests in the United States, and they're struggling with a workload that has exploded since President Bush signed the education reform package in 2002.
"The testing industry in the US is buckling under the weight of NCLB demands," said Thomas Toch, co-director of Education Sector, a think tank based in Washington.
When Education Sector surveyed 23 states in 2006, it found that 35 percent of testing offices in those states had experienced significant errors with scoring and 20 percent did not get results "in a timely fashion."
More problems were seen in Illinois this month, when students took achievement tests that contained as many as 13 errors, officials said.
Illinois isn't the only state that has experienced difficulties:
Oregon's Education Department complained that a computerized test was plagued by system problems. The state has sued test company Vantage Learning for breach of contract , and thousands of students who haven't completed online exams will take them in May using paper and pencil.
Connecticut last year fined Harcourt $80,000 after a processing error caused incorrect scores for 355 students in 2005. While that's a fraction of the state's 41,000 pupils who took the test, state officials had to notify 51, or nearly a third, of all districts, about wrong scores.
The Texas Education Agency passed 4,160 10th-graders who initially failed the math section of the Texas Assessment of Knowledge and Skills in 2003 after officials discovered a test question had more than one correct answer.
Pearson Educational Measurement apologized last year after it reported more than 900,000 Michigan results weeks late. In 2003, previous vendor Measurement Inc. delivered 3,400 scores months late and nearly 1,000 results went missing.
Education officials in Alabama said a testing company mistakenly failed some schools while passing others that should have failed on the 2005 test.
The number of students tested has risen sharply since the No Child Left Behind Act took effect. Illinois, for example, used to test only third-, fifth-, and eighth-graders but now tests students in third through eighth grades.