Click amount to donate direct to CounterPunch
  • $25
  • $50
  • $100
  • $500
  • $other
  • use PayPal
Keep CounterPunch ad free. Support our annual fund drive today!

Grading Teachers, Failing Kids


What would children gain from teachers who have the highest evaluations as measured by the metric that Mayor Rahm Emanuel wants to implement for Chicago’s public school (but not charter school) teachers?  This is precisely what three Columbia and Harvard economists researched in a study that has received wide attention from the media and politicians.  According to the authors’ own interpretation—the sky.  But if you read the study itself—nothing at all.

The study examined the incomes of adults who, as children in the 4th through the 8th grades, had teachers of different “Value Added” scores, with Value Added defined as improvement in the scores of students on standardized tests.  The researchers found that the average wage and salary of a 28 year old who had an excellent teacher was $20,509 in 2010 dollars, $182 higher than the average annual pay of all 28 year olds in the study.

How does this compare to the average salary and wage of a 28 year old in this country? The authors chose not to make the comparison, but we can make it for them.  They excluded from their study people whose income was higher than $100,000. As we shall see, this exclusion is problematic; but to do the comparison we must do the same. The average salary and wage in 2010 of a 28 year old who earned less than $100,000 a year was $29,041, 42% higher than the income of a 28 year old in the Columbia-Harvard study who had an excellent teacher. In other words, even if we accept the spin the authors put on their numbers, having an excellent teacher does not pull people out of poverty.

But tiny as it is, even the gain of $182 a year from having a high “value-added” teacher may not really exist.   First, the exclusion of people with high incomes involved some 4,000 individuals, or 1.2% of the sample. The authors justify it by claiming that such people are outliers. But what if it turned out those high income earners had “bad” teachers? Including them in the study would have completely changed the results. Excluding a large number of the best performers from a study about the effect of teaching seems strange.

But that’s not all.  When the authors examined the incomes of 30 year olds they found no statistically significant result.   Why? In the study the authors explain this by the small number of 30 year olds in their sample.  And in their interviews with the media and in public presentations  the authors do not mention this result at all. Yet the number of 30 year olds in their sample is 61,639, and these are all
students who went to school in the same city.  Is this really a small sample? To gain an appreciation for the size of the sample consider the fact that in order to estimate the unemployment rate that it publishes every month, the Bureau of Labor Statistics relies on a national survey of 60,000 households with an average of 1.95 adults in each. Surely if 120,000 people are a good size sample to study a labor force of 150 million people spread all over the country, a sample of 61,639 is a good size sample to study a population of fewer than 5 million elementary school students who all come from the same school system. By any measure the sample size is not only adequate, it is fantastically huge, and the result is not statistically significant.

The statistically insignificant results for 30 year olds may have been inconvenient for the authors for another reason. An increase of $128 a year is small by any standard, so the authors resorted to estimating a lifetime increase in earnings due to this increase. To do this they assumed that the percentage increase in income, 0.9 of one percent, which they estimated for age 28, holds for each year of a person’s working life. And perhaps this is why the authors chose to ignore the results for the 30 year olds. What their findings actually permit them to claim truthfully is that an excellent teacher increases average annual income by $128 at age 28, and that this effect disappears at age 30. But then there would have been nothing to report.

Does teacher quality matter?  Of course it does, and it should, therefore, be evaluated:  by peers, principals, outside experts, students and parents.  But it cannot be measured, and Mayor Emanuel of Chicago knows it.  Why else would the non-union charter schools be exempted from the same measurement?   The evaluation method the mayor wants to implement is nothing more than a union-busting, pro-privatization trick that is based on partisan economics.

Moshe Adler teaches economics at Columbia University and at the Harry Van Arsdale Center for Labor Studies at Empire State College. He is the author of Economics for the Rest of Us: Debunking the Science That Makes Life Dismal (The New Press, 2010),  which is available in paperback and as  an e-book.


Moshe Adler teaches economics at Columbia University and at the Harry Van Arsdale Center for Labor Studies at Empire State College. He is the author of Economics for the Rest of Us: Debunking the Science That Makes Life Dismal (The New Press, 2010),  which is available in paperback and as an e-book and in Chinese (2013) and Korean (2015) editions.

More articles by:

2016 Fund Drive
Smart. Fierce. Uncompromised. Support CounterPunch Now!

  • cp-store
  • donate paypal

CounterPunch Magazine


October 26, 2016
John W. Whitehead
A Deep State of Mind: America’s Shadow Government and Its Silent Coup
Eric Draitser
Dear Liberals: Trump is Right
Anthony Tarrant
On the Unbearable Lightness of Whiteness
Mark Weisbrot
The Most Dangerous Place in the World: US Pours in Money, as Blood Flows in Honduras
Chris Welzenbach
The Establishment and the Chattering Hack: a Response to Nicholas Lemann
Luke O'Brien
The Churchill Thing: Some Big Words About Trump and Some Other Chap
Sabia Rigby
In the “Jungle:” Report from the Refugee Camp in Calais, France
Linn Washington Jr.
Pot Decriminalization Yields $9-million in Savings for Philadelphia
Pepe Escobar
“America has lost” in the Philippines
Pauline Murphy
Political Feminism: the Legacy of Victoria Woodhull
Lizzie Maldonado
The Burdens of World War III
David Swanson
Slavery Was Abolished
Thomas Mountain
Preventing Cultural Genocide with the Mother Tongue Policy in Eritrea
Colin Todhunter
Agrochemicals And The Cesspool Of Corruption: Dr. Mason Writes To The US EPA
October 25, 2016
David Swanson
Halloween Is Coming, Vladimir Putin Isn’t
Hiroyuki Hamada
Fear Laundering: an Elaborate Psychological Diversion and Bid for Power
Priti Gulati Cox
President Obama: Before the Empire Falls, Free Leonard Peltier and Mumia Abu-Jamal
Kathy Deacon
Plus ça Change: Regime Change 1917-1920
Robin Goodman
Appetite for Destruction: America’s War Against Itself
Richard Moser
On Power, Privilege, and Passage: a Letter to My Nephew
Rev. William Alberts
The Epicenter of the Moral Universe is Our Common Humanity, Not Religion
Dan Bacher
Inspector General says Reclamation Wasted $32.2 Million on Klamath irrigators
David Mattson
A Recipe for Killing: the “Trust Us” Argument of State Grizzly Bear Managers
Derek Royden
The Tragedy in Yemen
Ralph Nader
Breaking Through Power: It’s Easier Than We Think
Norman Pollack
Centrist Fascism: Lurching Forward
Guillermo R. Gil
Cell to Cell Communication: On How to Become Governor of Puerto Rico
Mateo Pimentel
You, Me, and the Trolley Make Three
Cathy Breen
“Today Is One of the Heaviest Days of My Life”
October 24, 2016
John Steppling
The Unwoke: Sleepwalking into the Nightmare
Oscar Ortega
Clinton’s Troubling Silence on the Dakota Access Pipeline
Patrick Cockburn
Aleppo vs. Mosul: Media Biases
John Grant
Humanizing Our Militarized Border
Franklin Lamb
US-led Sanctions Targeting Syria Risk Adjudication as War Crimes
Paul Bentley
There Must Be Some Way Out of Here: the Silence of Dylan
Norman Pollack
Militarism: The Elephant in the Room
Patrick Bosold
Dakota Access Oil Pipeline: Invite CEO to Lunch, Go to Jail
Paul Craig Roberts
Was Russia’s Hesitation in Syria a Strategic Mistake?
David Swanson
Of All the Opinions I’ve Heard on Syria
Weekend Edition
October 21, 2016
Friday - Sunday
John Wight
Hillary Clinton and the Brutal Murder of Gaddafi
Diana Johnstone
Hillary Clinton’s Strategic Ambition in a Nutshell
Jeffrey St. Clair
Roaming Charges: Trump’s Naked and Hillary’s Dead
John W. Whitehead
American Psycho: Sex, Lies and Politics Add Up to a Terrifying Election Season
Stephen Cooper
Hell on Earth in Alabama: Inside Holman Prison
Patrick Cockburn
13 Years of War: Mosul’s Frightening and Uncertain Future