Prof. Jesse Rothstein Economics 196 Fall 2011 Some background  Measuring teacher quality: “Value added models”  VA modeling as a search for causal effects  Evidence on VA models  Connecting the evidence to policy Rising spending  Stagnant achievement  Important, persistent gaps  U.S. falling behind Rising spending  Stagnant achievement  Important, persistent gaps  U.S. falling behind Rising spending  Stagnant achievement  Important, persistent gaps  U.S. falling behind Rising spending  Stagnant achievement  Important, persistent gaps  U.S. falling behind Rising spending  Stagnant achievement  Important, persistent gaps  U.S. falling behind Not all of this evidence is airtight ◦ Sample selection & 17-year-olds  Some are cherry-picked  And some interpretations are tendentious ◦ Should special ed spending raise SAT scores?NAEP Math NAEP ReadingSource: Chay, Guryan, and Mazumder, 2009Special Education Enrollment (as a percentage of total enrollment)02468101214161977 1982 1987 1992 1997 2002YearPercentageall disabilitiesspecific learning disabilities Desegregation  More funds  More equal funding  Vouchers  Charters  Each came with a lot of fanfare, but little evidence. Most did not change the world.  Today’s version: Teacher quality “the single most important factor determining whether students succeed in school is not the color of their skin or their ZIP code or even their parents’ income – it is the quality of their teacher” — Education Manifesto, signed by Joel Klein, Michelle Rhee, and 14 other superintendents, Oct. 2010  “We know what works. What’s required, then, to get results from any school is no longer a mystery.…[T]he single most important factor in a student’s success after their parent is the person standing at the front of the classroom.” — President Obama, speech at TechBoston Academy, March 2011  “We know that of all the variables under a school’s control, the single most decisive factor in student achievement is excellent teaching.” — Bill Gates, “How teacher development could revolutionize our schools,” Washington Post, Feb. 2011 Having a top-quartile teacher rather than a bottom-quartile teacher four years in a row would be enough to close the black-white test score gap.  Having an above average teacher for five years running can completely close the average gap between low-income students and others.  A teacher one standard deviation better than average raises each student’s lifetime earnings by $20,000.  Replacing the bottom five percent of teachers with average teachers would raise the present value of future U.S. GDP by $100 trillion. None of these derive from interventions. 23 “the single most important factor determining whether students succeed in school is not the color of their skin or their ZIP code or even their parents’ income – it is the quality of their teacher” — Education Manifesto, signed by Joel Klein, Michelle Rhee, and 14 other superintendents, Oct. 2010  “We know what works. What’s required, then, to get results from any school is no longer a mystery.…[T]he single most important factor in a student’s success after their parent is the person standing at the front of the classroom.” — President Obama, speech at TechBoston Academy, March 2011  “We know that of all the variables under a school’s control, the single most decisive factor in student achievement is excellent teaching.” — Bill Gates, “How teacher development could revolutionize our schools,” Washington Post, Feb. 2011 “the single most important factor determining whether students succeed in school is not the color of their skin or their ZIP code or even their parents’ income – it is the quality of their teacher” — Education Manifesto, signed by Joel Klein, Michelle Rhee, and 14 other superintendents, Oct. 2010  “We know what works. What’s required, then, to get results from any school is no longer a mystery.…[T]he single most important factor in a student’s success after their parent is the person standing at the front of the classroom.” — President Obama, speech at TechBoston Academy, March 2011  “We know that of all the variables under a school’s control, the single most decisive factor in student achievement is excellent teaching.” — Bill Gates, “How teacher development could revolutionize our schools,” Washington Post, Feb. 2011 “the single most important factor determining whether students succeed in school is not the color of their skin or their ZIP code or even their parents’ income – it is the quality of their teacher” — Education Manifesto, signed by Joel Klein, Michelle Rhee, and 14 other superintendents, Oct. 2010  “We know what works. What’s required, then, to get results from any school is no longer a mystery.…[T]he single most important factor in a student’s success after their parent is the person standing at the front of the classroom.” — President Obama, speech at TechBoston Academy, March 2011  “We know that of all the variables under a school’s control, the single most decisive factor in student achievement is excellent teaching.” — Bill Gates, “How teacher development could revolutionize our schools,” Washington Post, Feb. 2011 Estimate a teacher’s effectiveness based on the average achievement of that teacher’s students.  Effective teaching = unusually large test score increases.  Generates estimates for all teachers – or at least for the roughly 40% whose students are tested.  Much cheaper than classroom observations.  Indicates wide variability in teacher quality.  But teachers aren’t magic: Moving from a 25th percentile teacher to a 75th percentile teacher raises an average student from the 50th percentile to about the 56th. Options: ◦ Average scores of her students ◦ Average gain scores ◦ Average scores, relative to other students who started in the same place. ◦ Something else?  How to choose? What are we trying to accomplish? Q: What is the estimand of interest? Q: What is the estimand of interest?