We continue yesterday’s posting with a few snippets from “Blame Game: Let’s Talk Honestly About Bad Teachers; Removing the lowest performing educators would pay big dividends, but saying so invites charges of “teacher bashing” by Andrew Rotherham October 20, 2011:

But let’s also be clear: there are more than a few teachers who shouldn’t be teaching.

Yet until recently there was little formal effort to recognize this. A landmark 2009 report by The New Teacher Project found that almost all — 99% — of teachers were given satisfactory evaluations even in the lowest performing schools.  Unfortunately, to raise these issues is to invite the charge of “teacher bashing.” 

When Stanford University economist Eric Hanushek looked at teacher performance he found that removing even the lowest five percent of performers could boost overall student achievement substantially. There are two key takeaways from this research. First, the lowest-performing teachers have a negative effect on student performance that is disproportionate to their numbers. Second, in practice this amounts to just one or two teachers per school on average. Most workplaces have similar problems.

Rotherham’s article above led to an exchange on teacher policy between economist Eric Hanushek, Stanford University and education historian Diane Ravitch posted at Eduwonk.com.  Hanushek begins with “Lifting Student Achievement by Weeding Out Harmful Teachers;” Ravitch response Here; Hanushek responded with “Ignoring Red Herrings;” and the last in the series, the Ravitch response Here.  This “back & forth” is particularly helpful because Ravitch raises many of the oft-heard objections to education reforms in our subject area.  It won’t take very long to read through the four essays and we strongly encourage it, however in our usual fashion we will paste some of the points Hanuchek makes below:

Lifting Student Achievement by Weeding Out Harmful Teachers

Almost everybody concerned with educational policy agrees on two things: the U.S. has a very serious achievement problem and teachers are the most important element in our school for addressing this problem. Beyond these, agreement breaks down.

…by replacing the bottom 5-10 percent of teachers with the average teacher found in today’s classrooms, research indicates that the achievement of U.S. students would rise from below the developed country average to near the top if not at the top.

… the variations in teacher effectiveness are huge, probably larger than most parents realize. Teacher effectiveness here is placed in simple terms – how much do students learn with a given teacher. Considerable research has gone into separating the impact of teachers on achievement from that of families, neighborhoods, and school peers. This research has produced extraordinarily consistent and similar results. From one perspective, a very good teacher can get a year and a half of student gain in learning over a school year, while a poor teacher gets half a year – a huge difference that leaves some students permanently harmed.

If, as noted, we could replace just the bottom 5-10 percent of teachers with an average teacher, we could expect the achievement of U.S. students to rise at least to the level of Canada and perhaps to Finland.

But think about it. Replacing the bottom 5-10 percent amounts to replacing two or three teachers in a school that has 30 teachers. Such a movement would not startle those in most businesses of the country. Surely it is less than seen in most law or accounting firms or in most hospitals.

Nobody doubts that there are teachers currently in our schools who should not be there. And, nobody doubts that the identity of these teachers is known to essentially everybody in the schools – from the principal, to the other teachers, to the students and parents, and to the union leaders.

The good teachers in the school are simply hurt by being lumped together with the small number of teachers that are harming our kids. Indeed, it is almost certain that the prestige of the profession along with teacher salaries would rise significantly if the good teachers were not tarnished by the bad.

Let me close with a couple of responses to people who are critical of this view. First, nothing says that one should use test scores to decide who these ineffective teachers are. In fact test scores are essentially irrelevant, because of the obviousness of the identity of these bad teachers, an identity that would be revealed by virtually any sensible evaluation system.

Second, it does not say that we need to replace an additional 5-10 percent each year. If we once got the stock of teachers up to par, we need only worry about the small percentage of new teachers each year that fall below the acceptable range. We are talking about trimming out just the new teachers who prove to be ineffective, not additional existing teachers.

This is not a call for replacing all teachers. Nor is it a call for returning all female doctors and lawyers to classrooms. It is simply a call for applying standard management practices to schools. When we entrust our children to a school, we should be able to trust that they are not harmed.

Ignoring Red Herrings” [any emphasis below is ours]

We have clear and consistent estimates about the variation in teacher effectiveness that exists in schools. The information comes from information on student test scores – something that is directly related to future student earnings and to the aggregate performance of the economy.

Undoubtedly other, unmeasured things beyond test scores are also important to students and to society, but there is no reason to believe that being good in these other things is hurt by having greater measured skills. And there is no reason to believe that teachers at the bottom in terms of producing measured skills are anything but the bottom in producing useful unmeasured skills.

It is a red herring to say there might be unmeasured other things that are also important.

Further, there is now consistent evidence that ratings by principals (on metrics other than test scores) are highly correlated with ratings on test scores at the top and bottom of the distributions. While there is confusion in the middle, there is not confusion at the top and bottom.

It is a red herring to say that different evaluation systems produce different results.                                                         

If we put together the impact of good teachers on student achievement and the impact of achievement in the lifetime earnings of students, we find that a good teacher (one in the top quarter in terms of effectiveness) each year produces over $350,000 more income for her students compared to an average teacher. But, symmetrically, a teacher in the bottom quarter subtracts $350,000 in income each year of teaching compared to an average teacher.

Ignoring these differences leads to huge inequities and to enormous waste in the potential of our students.

It is a red herring to point to other, complementary policies for improving teacher effectiveness without acknowledging the importance of starting with effective teachers.

Finally, it is fine to talk about teacher turnover, but not all teacher turnover is bad. If we move a bad teacher out of a school serving disadvantaged students, it is not a bad thing. The turnover rate in teaching is no different from that in other professions, and the initial turnover in teachers should not be used as a reason for ignoring the effectiveness of teachers. There is an excess supply of potential teachers. The shortage is not teachers per se but effective teachers.

It is a red hearing to say that teacher turnover is high without considering the implications for teacher effectiveness and ultimately for student achievement.

I have focused on one specific policy – eliminating the teachers that are harming our children. Diane wants to introduce the idea that, while there are teachers who are harming kids, we should not deal with them because there might be some residual uncertainty about the very last teacher who is in this group.

She repeatedly use the word “firing” to conjure up images of large, unjust, and arbitrary actions. To the contrary, it is simply good management to move a very small number of ineffective people out of the front line of schools. And by so doing, it acts to elevate the status of the vast majority of effective teachers.

Policy by red herring seldom leads to good policy.  It certainly does not when considering teacher policy.

We will continue our series tomorrow with Good Teachers/Lasting Gain…

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