The forces opposed to high-stakes assessment tests have their Montgomery, and it’s Snohomish.

When more than 550 sets of parents—about one out of 10—in this small town west of Seattle refused to let their children take the Washington State Measurements of Student Progress exam in April, they moved the anti-testing movement to a new phase of civil disobedience.

From two at an elementary school in Portland, Maine, to 550 in Snohomish, to 1,427 in Colorado, frustrated families that oppose the high-stakes tests required by the 11-year-old No Child Left Behind law are deploying a new weapon: keeping their kids from taking them.

“Talking to those in power has not accomplished anything,” says Tim Slekar, an associate professor of teacher education at Pennsylvania State University's Altoona campus and an outspoken opponent of the high-stakes tests. “But when you get larger groups together to make this kind of statement, it empowers the movement.”

And momentum for the so-called “Opt-Out” movement is growing. The group of 1,427 children whose parents kept them from taking last year’s Transitional Colorado Assessment Program (TCAP) was four times the number who did so the year before. In June, parents at 61 schools in New York State refused to let their students “field-test” a new exam being developed for fourth- through eighth-graders. And in Washington D.C., a session about opting out presented by Slekar and others at the annual August convention of the grassroots organization Save Our Schools, drew a standing-room-only crowd.

This development comes even as assessment tests have been swept back to the forefront of public attention by everything from the Chicago teachers’ strike to debate during the Republican convention over the No Child Left Behind Act.

The number of students opting out of state tests, though growing, remains small. The 61 schools that saw boycotts of the New York State field test, for instance, were a tiny fraction of the 900 public schools where there were no boycotts. But these boycotters could eventually have an effect, including on the trend toward using value-added analysis of teachers’ effectiveness based on students’ test scores, according to Douglas Harris, a professor of educational policy studies at the University of Wisconsin. That’s because widespread resistance to assessment tests would affect their usefulness in evaluating teachers.

“The long-term impact could be significant,” says Harris. “Given the tension in Chicago and elsewhere over teacher evaluations, one way it might grow is that you could begin to see parents and teachers banding together on this.”

The protests are helping to make political leaders even more acutely conscious of objections to the test, he says. “Policymakers certainly recognize that we may have gone a little too far in the focus on standardized tests, and you can see that in the Republican platform and how they’re having a bit of interparty dispute of their own on whether No Child Left Behind should continue. And when you’re talking about that, you’re talking about testing.”

Many things are fueling this, in addition to student anxiety and adult anger over an evident emphasis on teaching to the tests. In New York, antagonism peaked when that field test was found to have questions that were confusing or that had no, or more than one, right answer. Other parents have balked at new assessment tests for kindergarteners (including one in New York City beginning this fall), for placement in gifted programs, or for students with learning disabilities. And some communities are unhappy about the status of their local schools being downgraded by testing irregularities and mismanagement.

“Enough is enough,” says Ceresta Smith, a teacher in the Miami-Dade public schools in Florida and a cofounder of United Opt Out. Smith kept her daughter from taking the Florida Comprehensive Assessment Test in the 10th grade when her district announced that it would use the test results to determine teachers’ merit pay. “I don’t want to be a party to this,” she says.

That sentiment is growing. The proportion of Americans who say there’s too much emphasis on testing has nearly doubled, from 20 percent in 1997 to 37 percent today, according to a Gallup Poll conducted for Phi Delta Kappa International. Among public-school parents the number is even higher, at 44 percent. And several new national organizations have sprung up to channel these sentiments, including United Opt Out and Time Out from Testing.

“There is a dichotomy in the country between popular opinion about assessment and inside-the-beltway politicians [who] think the way to deal with the failure of test-driven education over the last decade is to double-down on it,” says Robert Schaeffer, public-education director of the advocacy group FairTest.

But the biggest motivation behind the opt-out movement appears to be the multimillion-dollar cost of high-stakes tests at a time when other education spending is declining. The Snohomish campaign, for instance, started as a protest against state budget cuts for education.

“We’ve spent billions and billions of dollars on high-stakes tests, and we have nothing to show for it,” says Angela Engel, an anti-test activist and author of Seeds of Tomorrow: Solutions for Improving Our Children’s Education, which offers alternatives to high-stakes tests. “We need to really change the conversation away from what are the test scores to what are we doing to improve conditions for the kids.”

The response of school and state officials has been varied. In Snohomish, the 550 elementary school students whose parents refused to let them sit down for the assessment tests—about 12 percent of the 4,501 third- through eighth-grade students due to take them—were simply sent to separate classrooms. But high school students in Washington and in 24 other states continue to be required to pass an exit exam to graduate, according to the Center on Education Policy. Smith’s daughter managed to get her high school diploma only because there’s a clause in Florida allowing a satisfactory score on the SAT or ACT test to stand in for a passing grade on the FCAT.

In Colorado, where an organization called the Coalition for Better Education is using billboards to encourage parents to opt out of the TCAP, schools that failed to achieve at least 95 percent participation on that test fell one category on the rankings scale—until this happened to 64 schools, including some in affluent communities, and legislators quietly changed the math and dropped the penalty.

“What they were seeing were these wealthy districts with a lot of irate parents who don’t like their scores messed with,” said Engel, who withdrew her own kids from taking the TCAP at their schools in a high-end Denver suburb.

Principals nonetheless reportedly push to have students take the tests, even citing the potential effect of lower education ratings on home values, says Fair Test’s Schaeffer. Only a few have put such things in writing, but one, the Granada Hills Charter High School in California, warns in its student handbook that anyone opting out of the assessment tests will be prohibited from participating in graduation, extracurricular activities, and sports. Testing advocates argue that opting children out of high-stakes tests is coddling them, and risks leaving them unprepared for the competitive nature of the working world.

Refusing to allow their children to participate in tests doesn’t fix what bothers parents most about high-stakes testing, Harris points out. “What parents don't like more than the tests themselves is how the tests are driving instruction, and opting out doesn’t do anything about that,” he says.

But Slekar, who has kept his own son from taking the Pennsylvania assessment test, contends that only this kind of action will bring any change at all. “The way you’re going to save schools is to end high-stakes testing,” he says, “and the way you’re going to end high-stakes testing is by parents doing this.”

Jon Marcus is a freelance journalist based in Boston, Mass.