Education policies that affect millions of students have long been tied to test scores, but a new paper suggests those scores are regularly misinterpreted.

According to the new research out of Mathematica, a statistical research group, the comparisons sometimes used to judge school performance are more indicative of demographic change than actual learning.

For example: Last week's release of National Assessment of Educational Progress scores led to much finger-pointing about what's working and what isn't in education reform. But according to Mathematica, policy assessments based on raw test data is extremely misleading -- especially because year-to-year comparisons measure different groups of students.

"Every time the NAEP results come out, you see a whole slew of headlines that make you slap your forehead," said Steven Glazerman, an author of the paper and a senior fellow at Mathematica. "You draw all the wrong conclusions over whether some school or district was effective or ineffective based on comparisons that can't be indicators of those changes."

[readon2 url="http://www.huffingtonpost.com/2011/12/14/test-scores-often-misused_n_1149501.html?ref=education&ncid=edlinkusaolp00000008"]Continue reading...[/readon2]