Why are public schools so bad at hiring good teachers?

The search for better economic policy.
July 11 2008 7:50 AM

Hot for the Wrong Teachers

Why are public schools so bad at hiring good instructors?

Is it possible to predict who will teach well?
Is it possible to predict who will teach well?

PS 49 in Queens used to be an average school in New York City's decidedly below-average school system. That was before Anthony Lombardi moved into the principal's office. When Lombardi took charge in 1997, 37 percent of fourth graders read at grade level, compared with nearly 90 percent today; there have also been double-digit improvements in math scores. By 2002, PS 49 made the state's list of most improved schools. If you ask Lombardi how it happened, he'll launch into a well-practiced monologue on the many changes that he brought to PS 49 (an arts program, a new curriculum from Columbia's Teachers College). But he keeps coming back to one highly controversial element of the school's turnaround: getting rid of incompetent teachers.

Firing bad teachers may seem like a rather obvious solution, but it requires some gumption to take on a teachers union. And cleaning house isn't necessarily the only answer. There are three basic ways to improve a school's faculty: take greater care in selecting good teachers upfront, throw out the bad ones who are already teaching, and provide training to make current teachers better. In theory, the first two should have more or less the same effect, and it might seem preferable to focus on never hiring unpromising instructors—once entrenched, it's nearly impossible in most places to remove teachers from their union-protected jobs. But that's assuming we're good at predicting who will teach well in the first place.

Advertisement

It turns out we aren't. For instance, in 1997, Los Angeles tripled its hiring of elementary-school teachers following a state-mandated reduction in class size. If L.A. schools had been doing a good job of picking the best teachers among their applicants, then the average quality of new recruits should have gone down when they expanded their ranks—they were hiring from the same pool of applicants, but accepting candidates who would have been rejected in prior years. But as researchers Thomas Kane and Douglas Staiger found, the crop of new teachers didn't perform any worse than the teachers the school had hired in more selective years.

This unexpected result is consistent with the findings from dozens of studies analyzing the predictors of teacher quality. Researchers have looked at just about every possible determinant of teaching success, and it seems there's nothing on a prospective teacher's résumé that indicates how he or she will do in the classroom. While some qualifications boost performance a little bit—National Board certification seems to help, though a master's degree in education does not—they just don't improve it very much.

It's worth keeping in mind that economists study changes in test scores, not love of learning or comprehension of course material—it's possible that some of the teachers who look good to researchers are just good at teaching to the test. Needing some measure of success in the classroom, economists mostly rely on "value added" in test scores—that is, how much students' scores improve as a result of a year in a teacher's classroom. Since researchers study entire school systems over many years, they're able to separate out how much of an individual student's improvement is due to personal circumstance and how much is the result of inspirational teachers. If a student's test scores increase year after year, then no teacher gets any credit for it; similarly, no one's on the hook for a bad student's repeated failure to progress.

What economists have found is that only one thing tells us how much a teacher will boost his students' test scores next year: the amount he raised test scores in previous years. A good teacher this year will very likely be a good teacher next year. Unfortunately, when making hiring decisions, principals rarely have that information at their fingertips. Most hiring decisions are made before applicants have a teaching record. And an individual school has neither the necessary data nor the ability to run the complicated regression analyses needed to discern whether an experienced teacher has had a positive effect on his students in the past.

Which leaves school officials in the position of having to find a way to get rid of the inevitable bad hires. Anthony Lombardi's approach at PS 49 put him at the top of the teachers-union hit list. (The union head refers to Lombardi as a "tyrant.") Lombardi placed higher demands on his teachers, requiring, for example, detailed and cogent lesson plans. (He recalls that some teachers had one-word class outlines before the new rules were put in place.) He also started showing up in class to keep tabs on what was going on. While he may not have been able to discern teaching quality from a résumé, he knew effective teaching when he saw it in the classroom. Teachers who either couldn't or wouldn't perform up to his standards were given an ultimatum: Request a transfer or get saddled with an unsatisfactory rating, leading to an onerous (for all concerned) two-year review. Since his arrival, a third of PS 49's teachers have been squeezed out through Lombardi's efforts.

Of course, this just meant they were moved to another classroom in another school, lowering the test scores of someone else's children. So while this might be a way of cleaning up PS 49, it's not much use in reforming an entire school system. New York's school chancellor, Joel Klein, has gotten rid of some teachers through a program that effectively gives them a golden parachute out of teaching—they aren't allowed into the classroom, though they stay on the payroll. But this is a very expensive Band-Aid.

What if there were a way to screen out the bad teachers before they get entrenched? Currently, New York City teachers get their union cards their first day on the job. In theory they're on probation for three years after that, but in practice very few are forced out. Lombardi suggests replacing this system with an apprenticeship program. Rather than requiring teaching degrees (which don't seem to improve value-added all that much), new recruits would have a couple of years of in-school training. There would then come a day of reckoning, when teachers-to-be would face a serious evaluation before securing union membership and a job for life.

Lombardi's proposal isn't without its problems and complications: What would the effect be on the morale of older teachers? Would the teachers unions ever agree to such a system? But none seems insurmountable. Researchers Kane and Staiger, together with coauthor Robert Gordon, have also suggested an apprenticelike system and have put forth a detailed proposal on how to implement it.

We live in an age of increasing inequality. While it's not fair to park the problem of global inequities at the doorstep of teachers unions, the continued floundering of public education in America is at least partly to blame: Education is an awfully good predictor of future earnings, and keeping bad teachers in classrooms filled with kids from poor families certainly helps to reinforce the cycle of poverty. The difference between a teacher in the 25th percentile (a very good teacher) and one at the 75th percentile (a not very good teacher) translates into a 10 percentile point difference in their students' test scores. (As a frame of reference, on the SAT, 10 percentile points translates into an 80 or so point difference in raw test score.) After a string of good teachers or bad teachers, it's easy to see how you can end up with very wide gaps in student achievement. And this is all the more tragic since at least part of the answer—doing a better job of evaluating and selecting teachers—is readily at hand.

Ray Fisman is a professor of economics at the Columbia Business School and co-author of The Org: The Underlying Logic of the Office. Follow him on Twitter.

TODAY IN SLATE

The World

How Canada’s Shooting Tragedies Have Shaped Its Gun Control Politics

Where Ebola Lives Between Outbreaks

Gunman Killed Inside Canadian Parliament; Soldier Shot at National Monument Dies

Sleater-Kinney Was Once America’s Best Rock Band

Can it be again?

Paul Farmer: Up to 90 Percent of Ebola Patients Should Survive

Is he right?

Science

“I’m Not a Scientist” Is No Excuse

Politicians brag about their ignorance while making ignorant decisions.

Technology

Driving in Circles

The autonomous Google car may never actually happen.

In Praise of 13th Grade: Why a Fifth Year of High School Is a Great Idea 

PowerPoint Is the Worst, and Now It’s the Latest Way to Hack Into Your Computer

  News & Politics
The World
Oct. 22 2014 6:30 PM The Tragedies That Have Shaped Canada's Gun Politics
  Business
Continuously Operating
Oct. 22 2014 2:38 PM Crack Open an Old One A highly unscientific evaluation of Germany’s oldest breweries.
  Life
Gentleman Scholar
Oct. 22 2014 5:54 PM May I Offer to Sharpen My Friends’ Knives? Or would that be rude?
  Double X
The XX Factor
Oct. 22 2014 4:27 PM Three Ways Your Text Messages Change After You Get Married
  Slate Plus
Tv Club
Oct. 22 2014 5:27 PM The Slate Walking Dead Podcast A spoiler-filled discussion of Episodes 1 and 2.
  Arts
Brow Beat
Oct. 22 2014 9:19 PM The Phone Call Is Twenty Minutes of Pitch-Perfect, Wrenching Cinema
  Technology
Future Tense
Oct. 22 2014 5:33 PM One More Reason Not to Use PowerPoint: It’s The Gateway for a Serious Windows Vulnerability
  Health & Science
Wild Things
Oct. 22 2014 2:42 PM Orcas, Via Drone, for the First Time Ever
  Sports
Sports Nut
Oct. 20 2014 5:09 PM Keepaway, on Three. Ready—Break! On his record-breaking touchdown pass, Peyton Manning couldn’t even leave the celebration to chance.