From the Wall Street Journal… I like this researcher’s thinking. If someone criticizes research, go back and rework it so it addresses the very faults they raised!
An excerpt from the article:
Critics of charter schools have long argued that any higher test scores were not necessarily attributable to anything the schools were doing, but to the students themselves, on the premise that only the most motivated students and families elected charters. Ms. Hoxby’s study sought to address that argument by comparing students who attend charters directly with similarly motivated students — those who sought to attend charters but were denied a seat through a random lottery. She concluded the charters did have a positive effect.
Link to article (only live for 7 days) http://online.wsj.com/wsjgate?subURI=%2Farticle%2FSB125358513141729871-email.html&nonsubURI=%2Farticle_email%2FSB125358513141729871-lMyQjAxMDI5NTIzMzUyODM1Wj.html