Today, bounteous new international academic achievement data were released, from the TIMSS and PIRLS battery of tests. The news for the United States wasn’t too bad, especially with the country ranking fairly high overall (but generally well below high-flying East Asian nations).

How have U.S. scores changed? On 4th grade mathematics average scores have risen precipitously, from 518 (out of 1000) in 1995 and 2003, to 541 in 2011. 8th grade scores were also up, but at a smaller clip, going from 492 in 1995 to 509 in 2011. Interestingly, scores rose ten points between 1995 and 1999, but only seven points between 1999 and 2011.

In science, 4th grade performance was pretty static: 544 in 2011, versus 542 in 1995, with a dip in the line in 2003 and 2007. 8th grade also saw some interesting kinks—the high score was 527 in 2003—but 2011’s score of 525 beat 1995’s 513.

Finally, only 4th graders are tested in PIRLS, the literacy test, and data only go back to 2001. Again there was a dip in the middle, but in 2011 the U.S. average was 556, versus 542 in 2001.

The really crucial question in all of this, of course, is why have the scores—both in the United States and other countries—moved as they have? Unfortunately these reports—at least the basic achievement parts and executive summaries—provide little insight into that. Yes, they tell us that schools with kids who do more math and reading with their parents get better scores, as do schools that are more orderly, but those could easily be functions of an underlying cause: say, families and communities that value education more. Indeed, as I found when looking at the empirical research on national curricular standards, one of the major possible reasons East Asian nations consistently outpace the rest of the world is a culture that values academic achievement, especially on material that is easily tested.

Unfortunately, some educationists are likely to seize on today’s news and declare that their pet policy variable—NCLB! Unionization! National standards! Spending! Even, to be fair, school choice!—explains high performance. But, just from the test scores, it is impossible to reach such conclusions. That requires much deeper analysis, such as the work Andrew Coulson has done in an effort to isolate the impact of  market-like factors on outcomes.

So for now, be happy: the United States has improved somewhat. But don’t make any policy declarations based on that.