Why
are public schools so bad at hiring good instructors?
By Ray Fisman Posted Friday, July 11, 2008, at 7:50 AM ET
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
incompetent20teachers.
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 ef fect, 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.
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 ana lyzing the predictors
of teacher quality. Researches 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 measure20of 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=2
0was 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't20allowed 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 tha t, 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 the Lambert Family Professor of Social Enterprise and research director of
the Social Enterprise Program at the Columbia Business School. His book with Ted Miguel,
Economic Gangsters, is forthcoming in October 2008.
Article URL: http://www.slate.com/id/2195147/
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