I certainly didn't, and this must have been flying under the radar for many of us who are not in such a field. So when I saw the title of the article, my first question was "What exactly is "math education research"?"
Mathematics-education research demands a rare combination of interests and skills, says Alan Schoenfeld, a mathematics education researcher at the University of California, Berkeley. Mathematics is important, of course; but math-education researchers also use social-science tools to study teacher behavior, student reasoning, educational equity, technology, and other topics. "A lot people who are brought up in the mathematics and the sciences tend to think the social stuff is soft and therefore not as intellectually interesting or rigorous," says Schoenfeld, who holds a Ph.D. in mathematics. But "math ed., properly done, is actually more challenging than mathematics, and that's because simple systems sit still and people don't."
And they can't seem to find enough people to do this? Wow!