Congressional candidate Carl DeMaio has a plan for San Diego schools: If you want students to learn more, pay the best teachers more money.

DeMaio announced on KUSI late last month that he’d be kicking off a series of education town hall meetings to invigorate the conversation about local school reform.

Here’s what DeMaio sees as the secret ingredient to better schools:

“Recent court cases, reported here on KUSI, have struck down a lot of the tenure requirements, so that you can’t just use time served. What I want to do is fill the vacuum with measurable performance standards – not dictated by the federal government, but developed locally, by school boards, teachers and parents. I want parental involvement in how we evaluate our teachers. But the most important thing is that we need to make sure that the dollars go to our best teachers. Our best teachers that are actually making progress with our kids should receive whatever available monies we have for pay increases or bonuses.”

DeMaio’s referring to Vergara v. California, a case in which the plaintiffs successfully argued that state laws protect ineffective teachers and disproportionately hurt students from low-income families.

In June, a judge agreed, though the decision is on hold while it’s being appealed.

It’s important to know that no changes have actually gone into effect. And it could be 18 to 24 months before the case is decided by the California Court of Appeal. If that decision is appealed, it could take another 18 to 24 months for California Supreme Court to weigh in.

That means the void that DeMaio is talking about isn’t as immediate as he’s describing.

To DeMaio’s broader point, however, the current system for evaluating teachers isn’t much more than a formality. In San Diego Unified, for example, principals stop by classes every one to five years and observe teachers, then decide how well teachers are doing.

Essentially, there’s no objective way to know who the best teachers actually are.

Over the years, efforts to reform this system in any meaningful way have been unsuccessful. Last spring, when Superintendent Cindy Marten proposed making student or parent feedback one piece of teacher evaluations, the teachers union pushed back.

And based on what the union president recently told me, that proposal will likely be reduced to a survey that parents or students fill out but nobody can see besides the teacher – if any changes are made at all.

Teachers unions argue it’s unfair to evaluate teachers by looking at test scores, because factors like poverty have more to do with students’ success than what teachers can do inside the classroom.

DeMaio didn’t mention test scores specifically, but said rating teachers should be done through objective measures which are decided by a various stakeholders including teachers, school boards and parents.

But if DeMaio is serious about including teachers in the conversation, that also means he’ll run into a hurdle: the teachers union. If history is any indication, they don’t take kindly to the notion of rewarding the best in their ranks.

Doing so creates competition among teachers, they say, and makes it less likely teachers will share effective strategies with their colleagues.

The idea certainly seemed like a nonstarter with Lindsay Burningham, the new president of the San Diego Education Association, who told me last month:

I think we’ve talked teaching evaluations in a circle and into the ground. It’s not just the pay that attracts teachers or keeps them in the profession. It’s the respect and resources they have at the schools they teach.

And if pay was tied to student performance, or test scores, I don’t think teachers would risk it. Because so many factors impact learning that have nothing to do with what happens in the classroom – things like poverty and home life.

Finally, there’s the question of merit-pay – or more importantly, whether it works at all. While it’s logical to think incentivizing teachers will encourage them to work harder and smarter – thus improving teacher quality – there’s evidence that approach isn’t as productive as it sounds.

Here’s how journalist Dana Goldstein described it in June, after the Vergara decision:

From 2009 to 2011, the federal government offered 1,500 effective teachers in 10 major cities—including Los Angeles—a $20,000 bonus to transfer to an open job at a higher poverty school with lower test scores. In the world of public education, $20,000 is a major financial incentive. All these teachers were already employed by urban districts with diverse student populations; they weren’t scared of working with poor, non-white children. Yet less than a quarter of the eligible teachers chose to apply for the bonuses. Most did not want to teach in the schools that were the most deeply segregated by race and class and faced major pressure to raise test scores.

Principals have known about this problem for ages. In Chicago, economist Brian Jacob found that when the city’s school district made it easier for principals to fire teachers, nearly 40 percent of principals, including many at the worst performing, poorest schools, fired no teachers at all. Why? For one thing, firing a coworker is unpleasant. It takes more than a policy change to overturn the culture of public education, which values collegiality and continuous improvement over swift accountability. That culture is not a wholly bad thing—with so many teachers avoiding the poorest schools, principals have little choice but to work with their existing staffs to help them get better at their jobs.

That’s not to say that any effort to find and reward effective teachers should be scrapped. But if the ultimate goal is to improve outcomes for kids, we’ll need to look to strategies that have proven effective, both in San Diego and elsewhere.

So perhaps it’s best that it may take time for the Vergara decision to be ironed out. That will give the community time to hash out what reforms it wants – whatever the outcome of the case.