From a paper by Solomon Garfunkel:
It should also be said that if one goes back 20 years or so, most of the principal investigators (PI’s) on math education projects were Ph.D. mathematicians who had so to speak ‘given their youth to the devil and were giving their old age to the lord’. In other words, they had taken an interest in mathematics education later in their careers. And to be honest many other math educators were persons who had originally tried to pursue careers as research mathematicians but were unable to complete their degrees. In any event, the PI’s on these projects had extremely strong mathematics backgrounds.In the U.S. at least, this has changed significantly. Mathematics education is now a well-established field unto itself and in many cases people highly successful in the field have relatively weak mathematical training. Increasingly, they are the principal investigators on new projects in mathematics education and they are the reviewers. They help decide what projects get funded and what projects don’t. And increasingly they are responsible for the Faffufnik-ChaimYankel Effect.