I asked my readers if Melinda Gates was right when she said that an effective teacher would get three times the “gains” of an ineffective reader and if you knew the source of this statistic or claim. I had many thoughtful replies. Many people had heard the claim, which was made not only by Melinda Gates but Michelle Rhee. Some attributed it to Eric Hanushek, some to Education Trust, some to William Sanders.

Surely there can be no doubt that some teachers are more successful than others, at least with some children in some years. Can all teachers get the same gains every year? Not so clear.

Imagine if every child in every classroom in the U.S. had an effective teacher every year, as Melinda Gates said would one day be possible due to the work of the Gates Foundation. That would mean that every child would gain 18 months of instruction every year. By the end of eighth grade, every child would be ready to go to college, having gotten the test score gains equivalent to twelve years of schooling. College-readiness by 13 or 14! That would surely be a break-through for our society and would change the nature of college-going.

In the search for the provenance of Melinda Gates’ statement, Gary Rubinstein seems to have cracked the code with his research. Gary teaches math at Stuyvestant High School and has his own blog, as you will see if you open the link. Gary tracked the claim back to a paper by Eric Hanushek in 1992 (which was cited by some other readers as well). His analysis is worth reading. What Rubinstein discovers about this 20-year-old study will surprise you and make you wonder why so many people are citing it today as definitive proof of certain policy ideas. No one offered any evidence that the 1992 study (or whenever it was conducted) has been replicated, so we don’t need to worry about a sudden explosion of 14-year-olds prepared to enter college.


PS: A reader on Twitter suggests that she would be satisfied if 14-year-olds arrived with appropriate skills and knowledge for their grade:

Margot Durkin ‏@mrsdurkinmuses

,@DianeRavitch re: M Gates: how about we strive to have every 14 year old ready for real high school work?