We often hear that Florida and U.S. students don't compare well to their peers internationally. But they don't take the same tests, or even test the same students, so how can you really tell?

The George W. Bush Presidential Center, with the help of University of Arkansas education reform professor Jay Greene, has now released a Global Report Card that attempts to put all testing data on an even field for comparison's sake. (You can read about the methodology here.) They use 2007 results, without much nod to the gains that Florida uses in its accountability reporting, and extrapolate.

Overall, the report suggests that even some of the districts considered best in the country are only middling on the world scene. How do our local districts shape up on its standard?

The average Hillsborough student performed at the 37th percentile in math, and the 47th percentile in reading. Pinellas came in at the 40th percentile for math and 52nd percentile for reading. Pasco: 33rd percentile for math and 50th percentile for reading. Hernando: 38th percentile for math and 50th percentile for reading.

Greene writes in Education Next: "Of course, the Global Report Card does not isolate the extent to which schools add or detract from student performance. Factors from student backgrounds, including their parents, communities, and individual characteristics, have a strong influence on achievement. But the GRC does tell us about the end result for student achievement of all of these factors, schools included. And that end result, even in our best districts, is generally disappointing."

The report is interactive, so you can explore it all you want. Is this kind of assessment useful in making comparisons, or not?