However Wisconsin's recall election turns out on Tuesday, teachers unions already appear to be losing a larger political fight—in public opinion. In our latest annual national survey, we found that the share of the public with a positive view of union impact on local schools has dropped by seven percentage points in the past year. Among teachers, the decline was an even more remarkable 16 points.
On behalf of Harvard's Program on Education Policy and Governance and the journal Education Next, we have asked the following question since 2009: "Some people say that teacher unions are a stumbling block to school reform. Others say that unions fight for better schools and better teachers. What do you think? Do you think teacher unions have a generally positive effect on schools, or do you think they have a generally negative effect?"
Respondents can choose among five options: very positive, somewhat positive, neither positive nor negative, somewhat negative, and very negative.
In our polls from 2009 to 2011, we saw little change in public opinion. Around 40% of respondents were neutral, saying that unions had neither a positive nor negative impact. The remainder divided almost evenly, with the negative share being barely greater than the positive.
But this year unions lost ground. While 41% of the public still takes the neutral position, those with a positive view of unions dropped to 22% in 2012 from 29% in 2011.
Political campaigns may already have noticed this shift. In a recent address on education, GOP presidential candidate Mitt Romney called teachers unions "the clearest example of a group that has lost its way."
The survey's most striking finding comes from its nationally representative sample of teachers. Whereas 58% of teachers took a positive view of unions in 2011, only 43% do in 2012. The number of teachers holding negative views of unions nearly doubled to 32% from 17% last year. Perhaps this helps explain why, according to education journalist and union watchdog Mike Antonucci, top officials of the National Education Association are reporting a decline of 150,000 members over the past two years and project that they will lose 200,000 more members by 2014, as several states have recently passed laws ending the automatic deduction of union dues from teachers' paychecks.
Teachers' increasingly critical stance toward their unions could have multiple causes. With unions on the defensive in state legislatures—on pension and medical benefits, evaluation systems and collective bargaining itself—some teachers may be concerned that unions aren't fighting hard enough for their interests. Others may be coming to the conclusion that unions are standing in the way of education reform.
But it's important not to overstate matters. Those taking the neutral position on our survey may be more sympathetic to the unions than it appears. To investigate this possibility, this year we gave half of those surveyed just two choices on their assessment of union impact, positive or negative (as opposed to the five nuanced options for other respondents). Among those asked the either-or question, 71% of teachers said unions had a positive impact. When push comes to shove, a clear majority of teachers still support their unions.
When the public was asked to choose between a simple positive and negative assessment, however, it split down the middle: 51% said unions had a negative impact, while 49% said their effect was positive. Whether this indicates a public-opinion tipping point is anyone's guess. But as outsize, underfunded teacher pension and medical benefits wreak havoc on school budgets, unions in Wisconsin and elsewhere are standing on increasingly shaky ground.
Mr. Peterson is a professor of government at Harvard and a senior fellow at the Hoover Institution. Mr. Howell is a professor of government at the University of Chicago. Mr. West is a professor at Harvard's Graduate School of Education.