By Dan Lips and Evan Feinberg

As Congress prepares to decide the future of No Child Left Behind, it seems everyone has become an expert on the law, including Comedy Central's Steven Colbert.

On a recent episode of The Colbert Report, Mr. Colbert shared his thoughts on the landmark federal education law, highlighting one of its central problems - how No Child Left Behind is causing states to dumb down state standards.

Colbert picked on Mississippi to demonstrate the problem. "Only 18 percent of fourth graders in Mississippi passed the standardized national (NAEP) reading test," Colbert explained. "Fortunately, it's the state reading test that counts. And 89 percent of Mississippi fourth graders passed the state test. You see, folks, with one deft move Mississippi is a shining example of how easy it is to succeed…if you simply redefine 'success' as 'below whatever you're currently achieving.'"

Colbert's report on No Child Left Behind came on the heels of two important studies that shed light on whether the landmark federal education law is working. The first report, from the Center on Education Policy, trumpeted good news for NCLB supporters.

The study looked at state proficiency scores and measured whether states were reporting improvement after the enactment of No Child Left Behind. It found that state math and reading scores had improved since the law had passed.

"American educators and students were asked to raise academic achievement, and they have done so," said Jack Jennings, president and CEO of the Center on Education Policy. Education Secretary Margaret Spellings also heralded the study's findings as evidence that "confirms that No Child Left Behind has struck a chord of success with our nation's schools and students."

But NCLB supporters shouldn't be too quick to celebrate. Days later, the Department of Education released a report that explains why state test scores alone don't show whether NCLB is working.

The Department report showed that state-defined proficiency standards are often far lower than proficiency standards on the NAEP, a national snapshot of American students' academic achievement. This means that states which claim large numbers of students scoring "proficient" on reading and math tests may just have easier tests than other states. Secretary Spellings called the report "sobering news."

The Department of Education report shows why, as Mr. Colbert explained, it is possible for 89 percent of Mississippi's fourth graders to score "proficient" in reading when only 18 percent scored "proficient" on the NAEP exam.

To be sure, state tests have always differed from the national exam. The real problem is that No Child Left Behind actually put in place incentives for states to weaken their standards - making it more pressing for them to meet political objectives than to improve student achievement by objective measures. Under NCLB, states are required each year to increase the percentage of students scoring "proficient" on state exams. Ultimately, the law requires that all students meet the goal of "proficient" on state tests by 2014.

This has led states to simply lower the bar, as humorously articulated by Mr. Colbert: "Well, that sounds hard. So here's what I suggest: Instead of passing the test, just have kids pass a test…. Eventually, we'll reach a point when 'math proficiency' means, 'you move when poked with a stick,' and 'reading proficiency' means, 'your breath will fog a mirror.'"

Researchers have studied trends in state testing and report that states are indeed participating in a "race to the bottom" by lowering state standards to meet NCLB goals. A 2006 study by University of California researchers found that the gap between state and NAEP proficiency scores had widened in 10 out of 12 states examined since NCLB was enacted. Professor Bruce Fuller, the lead author of the report, pointed to the likely reason: "State leaders are under enormous pressure to show that students are making progress. So they are finding inventive ways of showing higher test scores."

The bad news is that this problem will worsen as the 2014 deadline approaches. If nothing changes, parents should expect to see significant increases in state tests scores. But this improvement probably won't be evident on the national measures like the NAEP.

Mr. Colbert's jokes aside, this isn't a laughing matter. No Child Left Behind was intended to strengthen accountability and transparency in public education, but it is actually having the opposite effect. The "race to the bottom" is threatening to erode real transparency about academic performance. Parents and taxpayers soon may not be able to judge whether their children are learning and whether their public schools are working.

This is just one of No Child Left Behind's significant flaws that must be addressed in the upcoming Congressional reauthorization debate.

Dan Lips is Education Analyst at the Heritage Foundation, www.Heritage.org.