Beginning teachers have better academic credentials than their predecessors did a decade ago, suggesting that tougher requirements at all levels — from the federal government to the local teacher's college — have forced teachers' colleges to improve offerings while luring more qualified candidates into teaching. The gains hold across gender, racial and ethnic lines.
Educational Testing Service. (2007). Teacher Quality in a Changing Policy Landscape: Improvements in the Teacher Pool. Princeton, NJ: ETS.
http://www.ets.org/portal/site/ets/menuitem.1488512ecfd5b8849a77b13bc3921509/?vgnextoid=1dec64a4785a6110VgnVCM10000022f95190RCRD&vgnextchannel=b8cc64a4785a6110VgnVCM10000022f95190RCRD