http://obs.rc.fas.harvard.edu/chetty/value_added.html

"When a high value-added (top 5%) teacher enters a school, end-of-school-year test scores in the grade he or she teaches rise immediately..."

... and students assigned to such high value-added teachers are more likely to go to college, earn higher incomes, and less likely to be teenage mothers. On average, having such a teacher for one year raises a child's cumulative lifetime income by $50,000 (equivalent to $9,000 in present value at age 12 with a 5% interest rate).

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