Good and Bad Teachers: How to Tell the Difference-Becker

Although the recent Chicago teachers’ strike of seven school days was their first strike in 25 years, the main disagreement with the city was not over the traditional bread and butter issue of pay and benefits. Rather it was centered on the criteria to be used in evaluating teachers to distinguish good teachers from bad ones. It might seem surprising that teacher evaluations were so contentious since the union had already forced Mayor Rahm Emanuel to take merit pay for good teachers off the negotiating table. However, being deemed a good teacher still has advantages, including that better-rated unemployed teachers receive higher priority when teaching positions become available.Moreover, the union is aware that merit pay will become more of an issue in the future.

Teacher unions have long argued that the main criteria to be used in determining whether teachers are effective or not should be variables like teaching experience and teaching credentials rather than subjective evaluations of principals and other administrators. The unions claim that these evaluations were likely to be biased because allegedly they would be greatly affected by whether administrators liked or disliked particular teachers instead of by their actual classroom performance.

Unions and their supporters have also argued that teacher evaluations by administrators or parents are not worth a lot because it is difficult to get agreement on who are the good and bad teachers. I would challenge that claim: most of the time students as well as teachers agree on who are the good and bad teachers. Even my grandchildren in the lower grades of elementary school are confident that they and other students know which teachers to avoid, and which to try to get. Nevertheless, to provide more objective measures, teacher evaluations have been shifting toward using performance on standardized tests that measure knowledge of math, science and English language-related subjects. Teachers whose students perform well on these tests are deemed good teachers, whereas those with poorly performing students are considered weak teachers.

Teacher unions all over the country have fought against using performance-based measures to evaluate teachers, but the unions are gradually losing this battle. More than half of all U.S. states have adopted policies that require teachers to be rated in part based on student performance, such as standardized test scores. Even in their “victory” in the Chicago strike, the teachers union could not eliminate the use of student performance measures in evaluating teachers, but succeeded only in getting its weight in teacher evaluations down to 25% in the first two years of the contract, 30% in the third year, and 40% in year 4-the city wanted a weight of 40% starting in teh first year of the contract.

Of course, actual test scores are not appropriate measures of teacher contribution since some teachers get students who are better prepared when they enter their classes. For this reason the criterion used in evaluating teachers by many school systems and also by academic articles on school reform is the value added (VA) by teachers to student performance; namely, the improvements in students’ test scores as a result of taking classes of different teachers. The New York Times and the Los Angeles Times have in recent years released VA results for some the teachers in the New York and Los Angeles school districts, despite the loud protests of teachers unions in these cities.

Even value added may not fully measure the relevant effects of teachers on student performance since, for example, a given improvement in test scores may be more (or less) important for students with low test scores than for those who had high scores. More importantly, the fundamental way to judge teachers is not how their students do on tests, but how different teachers affect the likelihood that their students finish high school and go to college, how teachers affect the earnings of their students after they enter the labor force, and whether their students get involved in gangs and crimes.

A small number of recent academic studies have tried to see how well VA measures predict how students do when they become adults. A summary of a good study along these lines by Raj Chetty, John Friedman, and Jonah Rockoff was published this summer in the journal Education Next under the title “Great Teaching”. They had access to data for a large urban school district that spanned the 20 years from 1988-89 through 2008-09. The data contained information on test scores for about 2.5 million children in grades 3 through 8, and also the schooling, and when available, earnings of the children after they finished these grades.

They find large effects on subsequent adult earnings when these young students had teachers who produced good improvements in test scores compared to the adult earnings of students who had teachers who produced little improvement in test scores. If teachers were paid in relation to their effects on the subsequent adult earnings of their students, these results imply that teachers with good VA ratings should be paid considerably more than teachers with bad ratings. Adopting such a payment system for teachers would produce an improvement in the quality of teaching because good teachers would be more willing to go into teaching at elementary and high school grades. Such a change may well induce an increase in overall spending on teachers’ salaries and benefits because taxpayers would be willing to support education more generously if they felt students were getting good and useful teaching.

Of course, further studies of the effects of teachers on value added and on variables like adult earnings may find much smaller effects than those found by Chetty, et al.  Yet their finding that good teachers make a big difference to student performance is not the least bit surprising. This makes it all the more unfortunate that for decades teachers unions have fought against merit pay for good teachers, no matter how “good” teaching were to be measured. Since parents are losing patience with bad teachers, I expect the issue of merit pay to be one of the coming battlegrounds between teachers unions, and school boards and parents that want to better prepare students for the rigors of the modern marketplace.

 

Comments

[Rick LeVan]

Becker, I like the article, but I wonder about the implications of the correlation between teachers improving test scores and the large effects on subsequent earnings. You seem to imply that because these students earn more, the teachers who taught them ought to be better. This is without doubt at least partially true.

But I think it could also be true that good grades serve as a signal where employers with imperfect information try to hire the students with the best grades (independently of how connected such grades are to expected job performance). If this is the case, then if everyone received higher test scores, it would just lead to signal inflation--not a general improvement in education.

How much research is there on the correlation between student success in mastering state exams and general success on the job?

Rick

[Aordover]

We want student performance to be included in teacher evaluation, but not all teachers have tested students, and class sections are not identical. So why not use aggregate student peformance across the school as a single score affecting all teachers, added to their individual, qualitative scores based on classroom observations...on the theory that the whole school contributes to good or poor test peformance? It's a whole-team score.

[Charles Bloch]

Good post. However, I'd point out that the average Asian IQ is only 106 (see http://psychology.uwo.ca/faculty/rushtonpdfs/PPPL1.pdf )

[Connor Lynch]

If students can tell the difference between good and bad teachers, why not let students (and their parents) rank teachers in order of preference and let teachers decide which students get to be in their classroom based on grades and behavior reviews? So each year, the students essentially compete to get into the best classrooms within each school.

The teachers most in-demand among the best students are probably the best teachers. Not only that, but the best students won't get bored by having to go at the pace of the slowest student in the grade. Obviously there are some details to iron out, such as how to discourage grade inflation, but overall I think it's a pretty solid way to go about things. A rudimentary version of this already exists with the AP/Honors/Regular distinctions, but giving students more choices, and earlier, could really do wonders.

Problem solved. Plus, this would yield an amazing amount of information about the problems facing different schools--for instance, in areas where teacher selection preferences tend to be more or less random, lack of parental involvement is probably more to blame for poor student scores than poor teaching.

[starsky]

Connor, your solution would be counter-productive, because it would perpetuate inequality. If the best students get to choose the best teachers, then that means the most at-risk students get stuck with the worst teachers. Those students who are most prepared, either because they have supportive parents who have time and resources to help them with homework, who actually get to eat breakfast before they come to school, are genetically gifted, etc., would benefit from better teachers. Meanwhile, those students who are already disadvantaged would get the worst teachers.

[Actualidad]

While I disagree with Connor's suggestion to let teachers decide which students get to be in their classroom, I think he is correct in pointing out that the teachers that are most preferred by the best students are likely to be "the best", and therefore deserve to be rated accordingly.

[Neilehat]

Why are we even concerned about education and the underpriveleged and underclasses? Why, "Let them eat cake"! Or do we still have a fundamental belief in the concept of Universal Public Education and the principles of Horace Mann...

[Jdwalton]

It was easier with nuns, the orders sent the bad ones to darn the altar linens...and I am not kidding.

Good parents make teaching a lot more efficient.

[Kathy]

Can someone please acknowledge that there is subjectivity in evaluations for all other jobs? And surprise, it isn't always fair. There is a fundamental problem with our public schools when so many teachers have such distrust of administrators, especially when they always come from the ranks of teaching.

Aordover, most classes don't have standardized testing but would you want to be evaluated on the performance of your entire peer group? In my job, we work just fine as a team but my performance is my own. In theory, if someone goes into the teaching profession, one hopes they are passionate about the success of students and will be willing to lend a hand to support other members of the school staff in order to have a fabulous and successful school.

Jdwalton, of course good parents make teaching a lot more efficient but I don't think our society is ready to put any type of requirements onto parents - then we end up punishing the students for the failings of their parents, and if a kid has parents who don't care, haven't they already been punished?

To use a military analogy, no one joins the military these days thinking they will never go to war, and no one should go into teaching thinking it will be utopia. It's a tough job but the rewards are better than just about any other job out there.