Education debates can be fierce. There are strong political interests and philosophical differences about what schools should do. We don't just have experiences in schools, we develop relationships and emotional bonds there. This means reasonable people can disagree --passionately--about schools and school reform.

That's exactly what's happening here in New Orleans. No city has ever eliminated attendance zones, sidelined the teacher unions, or turned almost all public schools into charters--and certainly no one has done these all at once. These revolutionary changes put New Orleans on the national stage. The temperature rises. The words get sharper.

J. Celeste Lay, my colleague at Tulane, has written that the "Charter experiment in New Orleans [is] a failure." Diane Ravitch, an education policy analyst has called it "the biggest scam in the history of public education." President Barack Obama has hailed the new system as "a model of innovation for the nation," and Gov. Jindal has said the change in New Orleans "has inspired our entire state." With such diametrically opposed conclusions, the truth almost has to be somewhere in between.

Paradoxically, these conclusions are so strong in part because the evidence is so weak. There are few facts to get in the way of interests, ideology, and emotion.

Two basic questions need answers before we can draw conclusions about our school reforms: First, what effects have the changes had on student learning and long-term outcomes? Second, what exactly caused these effects?

We cannot yet answer these questions. As Tulane's Cowen Institute has shown, test scores and graduation rates have gone up considerably. Critics point out that the scores are still very low--many schools are still in the D and F range. But the only way to get the scores to an acceptable level is to improve, and the trends suggest that's happening.

It's not just the reforms influencing the scores, however. Reform critics argue that the upward trend is exaggerated because Katrina hit the lowest income students hardest and they didn't return. That's unfortunately true to some degree, but the best evidence suggests striking similarity in the incomes of today's public school students and their pre-Katrina counterparts. If anything, the trauma and disruption among returning students could actually be pulling down the city's test scores.

On the other hand, supporters of the reforms tend to take the scores at face value. But high-stakes testing creates incentives to drill students with questions just like those on the tests. This makes the scores go up without any real improvement in learning. Research in other states suggests that this type of teaching to the test is a common response to accountability.

So, high-stakes testing probably exaggerates the upward learning trend, while the lingering trauma and disruption of Katrina pull it back down. How much? We don't know yet, and that makes the trends hard to interpret.

Since public schooling is about serving all students, we must also ask tough questions about our most vulnerable students. Many lawsuits and complaints have been filed on behalf of special education students, students whose first language is not English and others. No doubt some of these complaints are based on real suffering of particular students, but are these problems widespread? Are the overall problems worse than before Katrina?

And whatever the effects are, why are they emerging? Are the reform effects driven by parental choice, charter schools, or the influx of ambitious, smart people who came to teach our children? Or is it because of factors outside the scope of the reforms, such as increased school funding levels post-Katrina and new facilities? We can't improve the schools if we don't know what's working and what's not.

In his compelling and inspiring new book, Tulane President Scott Cowen argues for letting data guide these conversations and decisions, and for bringing all sides to the table. I couldn't agree more. Working together with reform supporters and opponents, teachers and community groups, and a team of university researchers, the Education Research Alliance for New Orleans will soon begin releasing its first reports to provide some answers.

Disagreement can be a good thing because it forces us to think carefully and explore other views. That's not happening here. Given the tragedy that created the reforms, our students, educators, and citizens deserve more real debate based not on trends and anecdotes, but hard evidence.

Douglas N. Harris is Director of the Education Research Alliance for New Orleans, Associate Professor of Economics, and University Endowed Chair in Public Education at Tulane University.