Monday, December 20, 2010

Comment To Effective Teachers Produce $400,000 In Student Earnings Gains

A comment I posted on The Economist Free Exchange blog, " "Wow" result of the day" about effective teachers producing a $400,000 income gain to students:
It is not doable. No one knows before the fact who is a good teacher or what observable characteristics make for a good teacher.

From the cited paper in the article:
"The related issue is what makes for an effective or ineffective teacher. The extensive research addressing this has found little that consistently distinguishes among teachers in their classroom effectiveness. Most documented has been the finding that master’s degrees bear no consistent relationship with student achievement (See Hanushek and Rivkin (2004, (2006)). But other findings are equally as interesting and important. The amount of experience in the classroom – with the exception of the first few years – also bears no relationship to performance. On average, a teacher with five years experience is as effective as a teacher with 25 years of experience. But, this general result about measured characteristics of teachers goes even deeper. When studied, most evidence indicates that conventional teacher certification, source of teacher training, or salary level are not systematically related to the amount of learning that goes on in the classroom. For example, two recent high quality studies of different preparation and entry routes into teaching compare the impact on student achievement of Teach for America (TFA) and other alternative routes into teaching with traditional teacher training (Boyd et al. (2006) and Kane, Rockoff, and Staiger (2008)). They find little differences by teacher training background."
The $400,000 number is about as meaningful and useful as if instead I computed how much money I could make in the stock market, if I only bought stocks that went up and not down. Just as I and everyone else do not know how to find (other than Bernie Madoff) anyone who never loses money in the stock market, we do not know how to find or train effective teachers.

The paper uses teacher quality as it starting point for student achievement improvement and ignores more cost effective alternatives:
"The analysis presented below is built on a simple premise: The key element defining a school’s impact on student achievement is teacher quality."
The NIH (National Institute of Health) has funded research that finds "Improving mothers' literacy skills may be best way to boost children's achievement"

" 'The findings indicate that programs to improve maternal literacy skills may provide an effective means to overcome the disparity in academic achievement between children in poor and affluent neighborhoods,' said Rebecca Clark, Ph.D., chief of the Demographic and Behavioral Sciences Branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute that funded the study."

Instead of paying more to teachers, just add literacy programs for mothers and watch our k-12 students improve. It will be much more cost effective and will improve k-12 results.
I would also add to my Economist comment that one has to factor in the cost of paying for ineffective teachers, since one cannot predict beforehand which teacher is a winner and which teacher is ineffective. It is similar to the venture capital industry. One cannot compute the returns in that industry by only looking at the winning investments and not the losers. Without knowing the hiring criteria for effective teachers, school districts will have to hire ineffective teachers along with effective teachers. The costs of paying salaries of ineffective teachers plus the lost earnings income of students in ineffective teachers' classrooms has to be subtracted from the $400,000 reported income gain number.

Also see my earlier blog posts on this topic:

"Improving Mother's Literacy Improves Disadvantaged Child's Academic Performance" and,

"We Do Not Know How to Improve Student Education Levels And High School Graduation Rates."


  1. How can they manage to tell that an effective teacher can procure such big amount? Also, how they can possibly monitor these teachers daily?

  2. Thank you, thats very interesting information. I need to share with my friends.

  3. Interesting and important information. It is really beneficial for us. Thanks