If the state tests are easier, how did they get that way?

The flat scores New York students received on a national math exam released today have led some to question the validity of the huge jump in state math scores over the same time period.

The results seem to support skeptics who have argued that the statewide exam questions have become easier and more repetitive, the scores inflated, and the number of questions required to pass so low students can hop the bar just by guessing.

“This is a documentation of persistent dumbing down by the state education department and lying to the public,” education historian Diane Ravitch wrote today in an e-mail. “Exactly what Arne Duncan has been saying: When states dumb down their standards, they are lying to the kids, their parents and the public.”

But the question remains: if state exams have gotten easier, how and why did that happen?

The state standards and cutoff scores for passage have been constant since the early 2000s. But the number of correct answers needed to pass has gradually declined since 2006. Each year, a panel of test experts and educators convene as the exams are being field tested and judge each year’s questions according to their difficulty levels. The test-maker, CTB/McGraw Hill, then adjusts how it converts the number of correct answers to the scale score he or she receives.

In recent years, the number of questions judged difficult on the exams has risen, and thus the number of correct answers needed to pass has fallen, test experts have said.

But a side effect of this process has been that those numbers have fallen so low that students who randomly guess their way through the exams are statistically likely to still receive a passing score. And, analysts of the exam have pointed out that virtually all students receive enough points on the free-response section of the exam that the bar for guessing on the multiple choice section is lowered even further.

The situation is complicated further by the fact that the test questions may not be as difficult as test-makers believe them to be, because of the way the state field tests the exams to gauge their difficulty before giving them to all students. In New York, students who sit for the field tests are told that the exam they are about to take is only experimental.

This creates a motivational problem, test experts have said, in which students don’t take the experimental tests seriously and perform worse than would on a real exam. The conclusions test-makers draw from the field test results are then flawed; the test questions could then seem more difficult than they are. That misunderstanding would then have repercussions as the number of questions required to pass are scaled downward.

This gradual process of lowering the standards on the state exams has happened entirely as the tests are developed. But experts also have not ruled out the possibility that external factors, such as increased teaching to the test, have also contributed to the swift rise in scores.

Daniel Koretz, the Harvard education professor who has written extensively about standardized testing, has told me that the “700-pound gorilla” in New York state was that no one yet knows if the state tests are measuring real learning, and if not, what exactly is wrong with them.

Koretz and another testing expert, Howard Everson, have been calling for more than a year for an independent academic study examining the state exams’ credibility.

Both Koretz and Everson suspect that a phenomenon called “score inflation” may have contributed to the jump in scores over the years since the tests were last overhauled. Score inflation happens when scores rise artificially because of factors other than true understanding of the content–because teachers have coached students on how to ace predictable tests, for example, or because they give students extra time.

The state has thus far declined the opportunity to participate in any studies looking at how credible the exam results are.

But the pressure is mounting to re-examine the state tests.

Everson, who also chairs a committee of test experts that oversees the state testing process, said this afternoon that he was glad that the national math scores have re-focused attention on possible problems with the state tests.

“I’m encouraged that the new chancellor and commissioner are taking this very seriously,” he said. “I don’t want them to lose their momentum, so if this gives them more fuel for the fire, I think that’s great.”