SEATTLE — Washington has good measures in place to prevent cheating on school tests, but it fails to conduct the types of post-test analysis that other states routinely use to detect cheating, The Seattle Times reported Sunday.

The state Office of the Superintendent of Public Instruction doesn’t look for erasure patterns on student answer sheets that suggest someone changed wrong answers to right ones — as dozens of teachers and principals in Atlanta are accused of doing. Nor does it look for improbably high gains in a school’s scores or look for other suspicious results, such as a class full of students with identical answers.

Instead, The Times wrote, Washington relies on whistle-blowers to report wrongdoing and on school districts to police themselves — an approach national testing experts describe as inadequate, especially as many states start using test scores to evaluate teachers and principals.

OSPI officials say they don’t need to spend time and money on such post-test analyses because they’re confident suspicious activity would be reported to them.

“Based on how closely we monitor and work with the school districts, we’ve not found any cause to ask for the additional funds,” said Christopher Hanczrik, the office’s director of assessment operations.

In the past year, two prestigious national organizations have recommended that post-test analysis be a regular part of any state testing program.

“A state’s primary obligation is to ensure that the scores reported on their tests are valid,” said Greg Cizek, a professor of educational measurement and evaluation at the University of North Carolina-Chapel Hill, “and if you don’t do any kind of post-test analysis, you can’t affirm that the scores are valid.”

Jim Wollack, a test-security expert at the University of Wisconsin, said states that forgo such analysis of school and district scores are blind to any misconduct happening at those levels.

The state of Georgia didn’t regularly look for suspicious erasure patterns until 2008, when The Atlanta Journal Constitution raised questions about a number of schools where test scores had increased improbably.

In one school, a large number of students who had failed the state test in the spring earned very high scores on retests in the summer.

Subsequent investigations have since spread to hundreds of schools across Georgia, leading to indictments earlier this year of nearly three dozen Atlanta educators who, under pressure to raise test scores, allegedly changed answers for years before they were caught.

Since 2008, cheating scandals have also emerged in Washington, D.C., Pennsylvania, Ohio and elsewhere, prompting calls for stricter test security.

“In every case we’ve seen when states or districts think there is no cheating going on,” Cizek said, “they are surprised to find out there is much more than they ever believed there was.”

A Government Accountability Office survey earlier this year found that 37 states reported doing some type of post-test analysis. Thirty-three said they investigate erasure patterns, and 28 reported looking for unusual score gains and losses.

Washington follows many of the national recommendations for preventing cheating in the first place, such as providing annual training for school-district staff, and requiring anyone who touches a state test to sign a statement saying he or she knows the rules.

OSPI has strict procedures for everything from how to lock up exams before and after they’re given, what teachers can say and do during testing, even what should happen if a student needs to use the bathroom.

The state asks school and district staff to report any irregularities, including inadvertent mistakes and suspected tampering. It also has a hotline for anonymous reports.

The state receives hundreds of reports each year about testing irregularities. This year, an Olympia science teacher turned himself in for using a photocopy of last year’s fifth-grade science test to help prepare students for this year’s exam. OSPI invalidated the scores of all 165 of his students.

But the state doesn’t look for cases like that on its own. Even when suspected cheating is reported, OSPI largely turns to districts to investigate themselves.

Hanczrik said state legislators have cut the state budget dramatically, and his office has just three people. The state pays $30 million a year to the contractor that develops and scores state tests, and an erasure analysis would cost $100,000 more, he said.

“It’s not being irresponsible,” he said, “it’s making the best choice we can, with the available resources.”