The Nov/Dec 2014 issue of the MIT alumni magazine, Technology Review, had a long cover story on inequality, "Technology and Inequality", by editor David Rotman. While it isn't particularly surprisingly that MIT thinks more spending on education is the solution to all problems I nonetheless found it irritating in this instance. Misdiagnosing a real problem is harmful not just because it encourages spending on solutions that will not work but also because it discourages investigating solutions that might work.
The problem with the MIT article (and many similar ones) is that it correctly notes that people who have completed more levels of education tend to earn more money in their subsequent careers and then jumps to the almost certainly false conclusion that the additional years of schooling are why they are more valuable employees. It seems far more likely that some people have more natural academic ability than others and that the traits that make them good students also make them good employees. So the educational system is just identifying students who will make especially good employees. For the most part students who do poorly in school do so because they lack natural academic ability not because their schools are especially bad. There is confusion on this point because average academic ability varies widely between schools so some schools have lots of high ability students who do well and other schools have lots of low ability students who do poorly. It is natural to think that schools where most of the students are doing well must be far superior to schools where most of the students are doing poorly. But in the United States this is not the case, schools (within the range commonly found) make little difference. Move a poor student to a "good" school and they are likely to continue to do poorly, move a good student to a "poor" school and they are likely to continue to do well. Furthermore what differences do exist are predominantly due to peer effects, it is better to be surrounded by good students than by poor students. And of course it is not possible for everybody to have mostly high ability classmates.
One of the traits which helps you do well in schools is of course intelligence or IQ which the article doesn't mention at all. I do not find it surprising people with IQs of 115 do better in school and in their work careers than people with IQs of 85. But schools (in the US) have little effect on IQ and more spending on education cannot be expected to significantly reduce IQ differences and hence income inequality stemming from them.
Nor do I find it surprising that IQ is becoming more important in the job market. In 1920 there were over 25 million horses and mules in the US, by 1960 this number had fallen to slightly more than 3 million (see here). Pure muscle power used to be worth a lot in the economy, now not so much. There is a real issue here but more education isn't the solution.
Showing posts with label education. Show all posts
Showing posts with label education. Show all posts
Sunday, February 15, 2015
Saturday, July 26, 2014
Reign of Error
I recently read "Reign of Error" a 2013 book by Diane Ravitch about American public schools. There are two main factions in US education debates. The traditional educational establishment as exemplified by the teacher unions which largely supports more of the same and the "reformers" who believe that major changes are needed including replacement of many of the current teachers. In this book Ravitch presents the establishment case, defending the status quo and attacking the reformers and their proposals. As long time readers of this blog know I am not a fan of either side in this debate. Nor did I particularly like this book. While I generally agree that the reform proposals are wrongheaded I sometimes found her arguments against them unconvincing. And I don't think her own proposals make a lot of sense.
The problem with the traditional educational establishment is that they have a grossly inflated opinion of themselves. They believe teachers are very important and therefore deserving of lots of pay and respect. While these views are understandable in union leaders it makes it difficult for them to respond effectively to the reform arguments that since teachers are so critical to the educational process society should expend much more effort in identifying and weeding out bad teachers and that this would significantly improve our schools.
In truth however teachers aren't very important in that (within the range commonly found in US schools) they have little influence on results. It matters much more who the student is (again within the range commonly found in US schools) than who the teacher is. Peers also have more effect on outcomes than teachers. This means it is difficult to distinguish between below average and above average teachers and that the payoff for replacing below average teachers with above average teachers is not all that large. So the reformer's obsession with replacing large numbers of current teachers makes little sense. Slightly below average teachers are difficult to identify and are not doing much harm anyway.
One way in which differences among students matter is that some students are brighter than other students. The establishment (including Ravitch in this book) ignores this (apparently for political correctness reasons). Of course any system for evaluating teachers that doesn't take ability differences into account will be grossly unfair but the establishment's unwillingness to acknowledge that ability differences exist handicaps their response.
As noted above I didn't always think Ravitch made the anti-reform case very well. She goes on about how factors beyond a teacher's control (like a parental divorce) can affect student results and that how this makes evaluating teachers on the basis of results unfair. But this is unconvincing. What matters is how the inevitable random noise compares to the differences in teaching ability you are trying to detect. As it happens because these differences are relatively small random noise is a significant issue making ranking individual teachers problematic. Note student rankings are subject to random noise too but because the differences in performance are relatively larger they are more reliable.
Ravitch also goes on about how charter schools can be more selective about their students. This is a legitimate point in so much as if charter schools are only admitting bright students this should be accounted for in evaluating their results. But if charter schools are gaining by excluding disruptive students this is a legitimate advantage which should not be discounted. Keeping disruptive students in mainstream public school classes is a policy decision that could be reversed. If it has bad effects it is perfectly legitimate to count them against public schools. Similarly placing students of widely varying ability in the same classes is a policy decision. If charter schools can do better by tracking again this is a legitimate advantage that should be acknowledged.
I also wasn't convinced by Ravitch's own proposals. She goes on and on about all the things schools should teach besides the basic reading, writing and arithmetic skills students need to function as adults. This is fine for the top students who can pick up the basic skills quickly and with little effort but problematic for those who can't.
Ravitch also advocates expanded preschool programs the benefits of which are not as well established as she claims. She cites the Perry Preschool Project in a misleading way:
... At the time, many people assumed that IQ was fixed and that interventions made no difference. Weikart set out to prove them wrong.
One might think from this and her subsequent discussion that the Project had succeeded in raising IQ. But in fact while the Perry Preschool Project claims many wonderful results raising IQ (permanently) is not one of them. See the discussion at page 16 here:
It is true that the High/Scope Perry Preschool program had a statistically significant effect on children’s IQs during and up to a year after the program, but not after that. ...
As for the other results one small 50 year old study is not entirely convincing. Some replications would be nice.
And Ravitch wants to reserve certain positions for professional educators. But being a professional educator is a lot like being a professional astrologer. There is no underlying generally accepted scientific body of knowledge involved. So I see no reason to give "professional educators" and their politically correct fad theories of the moment undue deference.
The book did have some interesting material. For example it presented data showing that test scores have improved somewhat over the last 30-40 years. If correct (I have not attempted to independently evaluate and verify this claim) this is a worthwhile corrective to the widespread gloom and doom stories.
But overall this book is pretty long and I didn't find it very interesting. I don't recommend it.
The problem with the traditional educational establishment is that they have a grossly inflated opinion of themselves. They believe teachers are very important and therefore deserving of lots of pay and respect. While these views are understandable in union leaders it makes it difficult for them to respond effectively to the reform arguments that since teachers are so critical to the educational process society should expend much more effort in identifying and weeding out bad teachers and that this would significantly improve our schools.
In truth however teachers aren't very important in that (within the range commonly found in US schools) they have little influence on results. It matters much more who the student is (again within the range commonly found in US schools) than who the teacher is. Peers also have more effect on outcomes than teachers. This means it is difficult to distinguish between below average and above average teachers and that the payoff for replacing below average teachers with above average teachers is not all that large. So the reformer's obsession with replacing large numbers of current teachers makes little sense. Slightly below average teachers are difficult to identify and are not doing much harm anyway.
One way in which differences among students matter is that some students are brighter than other students. The establishment (including Ravitch in this book) ignores this (apparently for political correctness reasons). Of course any system for evaluating teachers that doesn't take ability differences into account will be grossly unfair but the establishment's unwillingness to acknowledge that ability differences exist handicaps their response.
As noted above I didn't always think Ravitch made the anti-reform case very well. She goes on about how factors beyond a teacher's control (like a parental divorce) can affect student results and that how this makes evaluating teachers on the basis of results unfair. But this is unconvincing. What matters is how the inevitable random noise compares to the differences in teaching ability you are trying to detect. As it happens because these differences are relatively small random noise is a significant issue making ranking individual teachers problematic. Note student rankings are subject to random noise too but because the differences in performance are relatively larger they are more reliable.
Ravitch also goes on about how charter schools can be more selective about their students. This is a legitimate point in so much as if charter schools are only admitting bright students this should be accounted for in evaluating their results. But if charter schools are gaining by excluding disruptive students this is a legitimate advantage which should not be discounted. Keeping disruptive students in mainstream public school classes is a policy decision that could be reversed. If it has bad effects it is perfectly legitimate to count them against public schools. Similarly placing students of widely varying ability in the same classes is a policy decision. If charter schools can do better by tracking again this is a legitimate advantage that should be acknowledged.
I also wasn't convinced by Ravitch's own proposals. She goes on and on about all the things schools should teach besides the basic reading, writing and arithmetic skills students need to function as adults. This is fine for the top students who can pick up the basic skills quickly and with little effort but problematic for those who can't.
Ravitch also advocates expanded preschool programs the benefits of which are not as well established as she claims. She cites the Perry Preschool Project in a misleading way:
... At the time, many people assumed that IQ was fixed and that interventions made no difference. Weikart set out to prove them wrong.
One might think from this and her subsequent discussion that the Project had succeeded in raising IQ. But in fact while the Perry Preschool Project claims many wonderful results raising IQ (permanently) is not one of them. See the discussion at page 16 here:
It is true that the High/Scope Perry Preschool program had a statistically significant effect on children’s IQs during and up to a year after the program, but not after that. ...
As for the other results one small 50 year old study is not entirely convincing. Some replications would be nice.
And Ravitch wants to reserve certain positions for professional educators. But being a professional educator is a lot like being a professional astrologer. There is no underlying generally accepted scientific body of knowledge involved. So I see no reason to give "professional educators" and their politically correct fad theories of the moment undue deference.
The book did have some interesting material. For example it presented data showing that test scores have improved somewhat over the last 30-40 years. If correct (I have not attempted to independently evaluate and verify this claim) this is a worthwhile corrective to the widespread gloom and doom stories.
But overall this book is pretty long and I didn't find it very interesting. I don't recommend it.
Sunday, December 1, 2013
Blog Roll
I have removed Nate Silver's 538 blog from my blog roll until such time as it restarts following Silver's move from the NYT to ESPN. I have added educationrealist a blog by a high school math teacher which seems mostly consistent with my views on education. Namely that the public schools are doing about as well as can be expected and that the main reason some kids do better academically than other kids is that some kids are smarter than other kids.
I have also added the Mr. Money Mustache blog by a man who retired (sort of) at age 30 by saving a ridiculous fraction of his income. I find his point of view interesting although I often disagree with it. And there would be problems if everyone tried to adopt his ideas.
I would like to add Kevin Drum's blog at Mother Jones to my blog roll but I have never been able to get the link to work properly in the Blog List widget. For some reason it sends you someplace else in the Mother Jones website although the link works fine in the body of a post as above. If anyone knows how to fix this let me know.
I have also added the Mr. Money Mustache blog by a man who retired (sort of) at age 30 by saving a ridiculous fraction of his income. I find his point of view interesting although I often disagree with it. And there would be problems if everyone tried to adopt his ideas.
I would like to add Kevin Drum's blog at Mother Jones to my blog roll but I have never been able to get the link to work properly in the Blog List widget. For some reason it sends you someplace else in the Mother Jones website although the link works fine in the body of a post as above. If anyone knows how to fix this let me know.
Sunday, February 6, 2011
Grading Teachers
This post is a follow up to my earlier post criticizing a paper, "The Economic Effect of Higher Teacher Quality", by Hanushek in which I address an issue raised in the comments.
Evaluating teachers based on how well their students do academically is difficult because teachers aren't (currently in the US) the only or even the most important factor in student success. So to properly measure the effect of teachers you first have to account as best you can for the other important factors. This is typically done by constructing a model which predicts how well a student will do based on everything besides their current teacher and then comparing this to their actual performance. This prediction will assume in effect that their current teacher is average. Any difference in actual performance is then attributed to the teacher being above or below average (depending on whether the student did better or worse than predicted). Clearly this will be very unreliable for a single student but the hope is that when averaged over many students the errors will tend to cancel out allowing differences in teacher quality to be detected.
What do these models look like. The most important factor in how well a student does is the characteristics of the student themself. This means things like how smart they are (in terms of IQ), how well educated their parents are, what their household income is etc. Such differences among students are far more important in predicting how well they will do academically than differences among their teachers. Since we are generally interested in evaluating the effect of a teacher over a school year another important factor is how well the student has done previously. If you are evaluating a third grade teacher and at the beginning of third grade a particular student is 4 months above their predicted grade level this must be accounted for when predicting where that student will be at the end of third grade (assuming an average teacher). Empirically students doing better or worse than expected at the beginning of a school year will still be doing better or worse than otherwise expected at the end of the school year but not by as much. So for example the student 4 months ahead of their predicted grade level might be expected to be 2 months ahead of their predicted grade level a year later. Similarly a student 4 months behind might be expected to be 2 months behind a year later. Models typically account for this by including a decay factor r so a student x months ahead of their expected grade level at the beginning of a school year will be predicted to be r*x months ahead of their otherwise expected grade level at the end of the school year. Note such models predict the difference n years later will (r**n)*x, this is a consequence of iterating the model predictions.
Hanushek uses such a model in his paper but does not appear to understand the implication noted above that any good or bad effects of for example 1-3 grade teachers will have largely decayed away by the time their students leave school and enter the work force. Hence as I noted before he does not appear to be correctly computing the predicted economic effects based on his own model assumptions.
Evaluating teachers based on how well their students do academically is difficult because teachers aren't (currently in the US) the only or even the most important factor in student success. So to properly measure the effect of teachers you first have to account as best you can for the other important factors. This is typically done by constructing a model which predicts how well a student will do based on everything besides their current teacher and then comparing this to their actual performance. This prediction will assume in effect that their current teacher is average. Any difference in actual performance is then attributed to the teacher being above or below average (depending on whether the student did better or worse than predicted). Clearly this will be very unreliable for a single student but the hope is that when averaged over many students the errors will tend to cancel out allowing differences in teacher quality to be detected.
What do these models look like. The most important factor in how well a student does is the characteristics of the student themself. This means things like how smart they are (in terms of IQ), how well educated their parents are, what their household income is etc. Such differences among students are far more important in predicting how well they will do academically than differences among their teachers. Since we are generally interested in evaluating the effect of a teacher over a school year another important factor is how well the student has done previously. If you are evaluating a third grade teacher and at the beginning of third grade a particular student is 4 months above their predicted grade level this must be accounted for when predicting where that student will be at the end of third grade (assuming an average teacher). Empirically students doing better or worse than expected at the beginning of a school year will still be doing better or worse than otherwise expected at the end of the school year but not by as much. So for example the student 4 months ahead of their predicted grade level might be expected to be 2 months ahead of their predicted grade level a year later. Similarly a student 4 months behind might be expected to be 2 months behind a year later. Models typically account for this by including a decay factor r so a student x months ahead of their expected grade level at the beginning of a school year will be predicted to be r*x months ahead of their otherwise expected grade level at the end of the school year. Note such models predict the difference n years later will (r**n)*x, this is a consequence of iterating the model predictions.
Hanushek uses such a model in his paper but does not appear to understand the implication noted above that any good or bad effects of for example 1-3 grade teachers will have largely decayed away by the time their students leave school and enter the work force. Hence as I noted before he does not appear to be correctly computing the predicted economic effects based on his own model assumptions.
Wednesday, December 29, 2010
Teacher Value
Last week Kevin Drum posted about a paper (pdf file, may be behind a paywall) by Eric Hanushek which estimates that a teacher one standard deviation above mean will improve the present value of a typical student's lifetime earnings by a substantial amount ($20000 with one set of assumptions). If correct these estimates would justify considerable effort and expense improving the average quality of teachers. However as readers of this blog know I doubt teachers make much difference. This paper has not convinced me otherwise.
The paper's estimates depend on a number of extremely debatable assumptions. Even worse it appears to contain a blatant error. One reason teachers don't matter much in the long run is the measured effects they do have tend to be temporary, fading away with time. Hanushek recognizes this and defines (p 14-15) a depreciation variable theta. But he does not appear to realize the effects are cumulative. After n years the effects of a particular teacher (as measured by achievement tests) are reduced by a factor of (1-theta)**n. But Hanushek assumes (1-theta) of the effect is permanent. Since theta is estimated as .3-.6 this makes a huge difference in his calculations. So, even granting the assumptions in his model, correctly computed the effect of an above (or below) average teacher will be much less than claimed.
The cumulative nature of this effect is clearly stated in one of the papers Hanushek cites Estimating Teacher Impacts on Student Achievement: An Experimental Evaluation ((c) 2008 Kane and Staiger, p.4):
Finally, in the experimental data we found that the impact of the randomly assigned teacher on math and reading achievement faded out at a rate of roughly 50 percent per year in future academic years. In other words, only 50 percent of the teacher effect from year t was discernible in year t+1 and 25 percent was discernible in year t+2. ...
The paper's estimates depend on a number of extremely debatable assumptions. Even worse it appears to contain a blatant error. One reason teachers don't matter much in the long run is the measured effects they do have tend to be temporary, fading away with time. Hanushek recognizes this and defines (p 14-15) a depreciation variable theta. But he does not appear to realize the effects are cumulative. After n years the effects of a particular teacher (as measured by achievement tests) are reduced by a factor of (1-theta)**n. But Hanushek assumes (1-theta) of the effect is permanent. Since theta is estimated as .3-.6 this makes a huge difference in his calculations. So, even granting the assumptions in his model, correctly computed the effect of an above (or below) average teacher will be much less than claimed.
The cumulative nature of this effect is clearly stated in one of the papers Hanushek cites Estimating Teacher Impacts on Student Achievement: An Experimental Evaluation ((c) 2008 Kane and Staiger, p.4):
Finally, in the experimental data we found that the impact of the randomly assigned teacher on math and reading achievement faded out at a rate of roughly 50 percent per year in future academic years. In other words, only 50 percent of the teacher effect from year t was discernible in year t+1 and 25 percent was discernible in year t+2. ...
Monday, June 7, 2010
Teacher bashing
Yglesias asks why advocates of performance pay for teachers are accused of teacher bashing since presumably as many teachers would benefit as would be hurt. I don't think this is any great mystery. The basic premise of such plans is that many schools are currently "failing" and that this is mainly the fault of the teachers at those schools. This seems like teacher bashing to me and unjustified at that since the premise is false.
Yglesias does identify a way in which teachers have brought this upon themselves. Teacher unions like to argue for higher wages on the basis that teachers are very important. This naturally suggests that perhaps greater efforts to identify and remove bad teachers are justified.
But while turning union propaganda against teachers in this way may have its attractions the fact remains that the evidence is that within the range of teacher quality currently found in US schools teachers aren't very important to outcomes. And, contrary to Yglesias, measuring individual teacher quality is very difficult as random variation will swamp any plausible differences in quality.
So the likely effect of any merit pay system is greater anxiety and uncertainly for teachers as some are randomly labeled bad with little if any benefit to students. It is no wonder teachers are largely opposed.
Yglesias does identify a way in which teachers have brought this upon themselves. Teacher unions like to argue for higher wages on the basis that teachers are very important. This naturally suggests that perhaps greater efforts to identify and remove bad teachers are justified.
But while turning union propaganda against teachers in this way may have its attractions the fact remains that the evidence is that within the range of teacher quality currently found in US schools teachers aren't very important to outcomes. And, contrary to Yglesias, measuring individual teacher quality is very difficult as random variation will swamp any plausible differences in quality.
So the likely effect of any merit pay system is greater anxiety and uncertainly for teachers as some are randomly labeled bad with little if any benefit to students. It is no wonder teachers are largely opposed.
Saturday, March 6, 2010
Scapegoats
Apparently President Obama has endorsed the recent mass firing of the teachers in a Rhode Island school where students are performing poorly. This is not too surprising since in his book "The Audacity of Hope" Obama claimed to believe that teachers are the most important factor in student performance. Which would make it logical to blame their teachers when students perform poorly. However in the real world teacher quality (within the range commonly found in the United States) hardly matters. Student performance is primarily determined by characteristics of the students themselves and secondarily by the characteristics of their classmates.
So while I believe it can be absurdly difficult to fire individual teachers for gross misconduct I am sympathetic to making it difficult to fire teachers in cases like this where teachers are being blamed for things they have little influence on. Of course this is a difficult case for the teacher's unions to make as if teachers don't matter much there is not much reason for them to receive premium pay.
So while I believe it can be absurdly difficult to fire individual teachers for gross misconduct I am sympathetic to making it difficult to fire teachers in cases like this where teachers are being blamed for things they have little influence on. Of course this is a difficult case for the teacher's unions to make as if teachers don't matter much there is not much reason for them to receive premium pay.
Wednesday, December 9, 2009
Bilingual education
Here is an article about the 1998 California proposition which limited bilingual education. It reports that the shift to English immersion has been quite beneficial for Hispanic students which is consistent with other accounts that I have read. Apparently, whatever the theoretical merits of bilingual education, as actually practiced in the United States it is actively harmful. This seems to be fairly well established. Still many liberals continue to reflexively support bilingual education in other parts of the country. Strange and ironic how separate and unequal classes have become politically correct.
Tuesday, November 10, 2009
Convenient falsehoods
I have been reading Obama's other book "The Audacity of Hope". It is pretty heavy going and I haven't finished yet. However I have completed chapter 5 "Opportunity" which contains some policy discussion. I disagree with much of it which doesn't mean too much as Obama and I have different priorities. What is more disturbing is that Obama seems to have difficulty critically evaluating proposals which appeal to liberal prejudices but won't actually work.
Obama uncritically supports ethanol on pages 169-170. Corn based ethanol is a good example of something which is superficially appealing but doesn't actually advance environmental priorities.
On page 161 Obama claims "... Recent studies show that the single most important factor in determining a student's achievement isn't the color of his skin or where he comes from, but who the child's teacher is. ...". Obama doesn't cite these studies so I can't specifically address them but this statement is contrary to numerous other studies that show the most important factor achievement in student achievement is the characteristics of the student and the next most important is the characteristics of his classmates. The quality of his teacher (within the range commonly found in American schools) hardly matters.
Finally on page 177 in discussing health insurance Obama claims "... The bigger the pool of insured, the more the risk is spread, the more coverage provided, and the lower the cost. ...". This misunderstands how insurance works. Pooling costs spreads them more equally but it doesn't reduce them. Pooling a bunch of high risks doesn't make them low risk or low cost.
This inability to recognize well intentioned nonsense won't matter too much if Obama appoints good advisers to handle the details. And Obama would hardly be the first President to be a big picture guy. Still Obama is the President we have at the moment and I would prefer a President with a better BS detector.
Obama uncritically supports ethanol on pages 169-170. Corn based ethanol is a good example of something which is superficially appealing but doesn't actually advance environmental priorities.
On page 161 Obama claims "... Recent studies show that the single most important factor in determining a student's achievement isn't the color of his skin or where he comes from, but who the child's teacher is. ...". Obama doesn't cite these studies so I can't specifically address them but this statement is contrary to numerous other studies that show the most important factor achievement in student achievement is the characteristics of the student and the next most important is the characteristics of his classmates. The quality of his teacher (within the range commonly found in American schools) hardly matters.
Finally on page 177 in discussing health insurance Obama claims "... The bigger the pool of insured, the more the risk is spread, the more coverage provided, and the lower the cost. ...". This misunderstands how insurance works. Pooling costs spreads them more equally but it doesn't reduce them. Pooling a bunch of high risks doesn't make them low risk or low cost.
This inability to recognize well intentioned nonsense won't matter too much if Obama appoints good advisers to handle the details. And Obama would hardly be the first President to be a big picture guy. Still Obama is the President we have at the moment and I would prefer a President with a better BS detector.
Thursday, October 1, 2009
Public Schools
One source of confusion regarding education policy is a lack of clarity about what the purposes of public schools are. As I see it public schools (K-12) have two main purposes. First to attempt to teach all their students those basic skills needed to function well as an adult in the United States. Second to identify and sort out the brighter students. In practice current schools attempt both of these. However, particularly in the higher grades, they seem more devoted to the second. In fact they sometimes seem actively hostile to teaching anything practical. Hence for example the trend towards dropping driver's ed.
But many policy discussions seem to only consider the first purpose. Devoting additional resources to the slower students makes sense when they are learning important basic skills. It makes no sense for classes like plane geometry which have little practical value and are used almost exclusively for sorting out the brighter students. Pushing slow students into such classes is just foolish. They don't need additional confirmation that they aren't as bright as other students and even if through great effort and perseverance they actually learn the material it won't do them any good.
But many policy discussions seem to only consider the first purpose. Devoting additional resources to the slower students makes sense when they are learning important basic skills. It makes no sense for classes like plane geometry which have little practical value and are used almost exclusively for sorting out the brighter students. Pushing slow students into such classes is just foolish. They don't need additional confirmation that they aren't as bright as other students and even if through great effort and perseverance they actually learn the material it won't do them any good.
Thursday, September 17, 2009
Education again
There were some belated comments to my recent education posts.
Regarding rubber rooms it was pointed out that it wouldn't matter that it is almost impossible to fire teachers after they get tenure if school districts never made mistakes when awarding tenure. This is true but unrealistic. Probably school districts could do a better job of selecting new teachers but perfection is impossible.
The New York City school district has been attempting to fire Colleen McGraham since 2005 when she developed a crush on a 15 year old boy. As of June 2008 the city had successfully appealed an arbitrator's 90 day suspension as too lenient but as far I can tell the case is still going on. Meanwhile she collects her salary.
In a similar case it took many years and multiple court appeals for the New York City school district to fire Cary Hershkowitz .
At least these teachers weren't criminally convicted of anything, unlike Alabama teacher Charlene Schmitz who continues to be paid while serving a 10 year sentence in federal prison for seducing a 14 year old.
I am unaware of any way that school districts can effectively screen out all teachers who will develop a propensity for this sort of thing.
These are extreme cases but it stands to reason that if it is difficult to fire teachers like these it will be almost impossible to fire teachers who are merely a little incompetent.
Regarding teachers there was some anecdotal evidence offered that teachers can make a differences. Some of this evidence was for remedial classes while I have been primarily talking about typical classes. More importantly I don't trust anecdotal evidence.
Consider this story :
Within a couple of weeks, Schonfeld, then a 46-year-old interior designer, got quickly and dramatically better, able once again to care for herself and her husband and daughter, no longer so convinced of her own worthlessness that she'd consider killing herself. For the next two months, she came back weekly for more interviews and tests and EEGs. And by the end of the study, Schonfeld seemed to be yet another person who owed a nearly miraculous recovery to the new generation of antidepressants -- in this case, venlafaxine, better known as Effexor.
A miracle drug? Not quite, she was on the placebo.
Regarding rubber rooms it was pointed out that it wouldn't matter that it is almost impossible to fire teachers after they get tenure if school districts never made mistakes when awarding tenure. This is true but unrealistic. Probably school districts could do a better job of selecting new teachers but perfection is impossible.
The New York City school district has been attempting to fire Colleen McGraham since 2005 when she developed a crush on a 15 year old boy. As of June 2008 the city had successfully appealed an arbitrator's 90 day suspension as too lenient but as far I can tell the case is still going on. Meanwhile she collects her salary.
In a similar case it took many years and multiple court appeals for the New York City school district to fire Cary Hershkowitz .
At least these teachers weren't criminally convicted of anything, unlike Alabama teacher Charlene Schmitz who continues to be paid while serving a 10 year sentence in federal prison for seducing a 14 year old.
I am unaware of any way that school districts can effectively screen out all teachers who will develop a propensity for this sort of thing.
These are extreme cases but it stands to reason that if it is difficult to fire teachers like these it will be almost impossible to fire teachers who are merely a little incompetent.
Regarding teachers there was some anecdotal evidence offered that teachers can make a differences. Some of this evidence was for remedial classes while I have been primarily talking about typical classes. More importantly I don't trust anecdotal evidence.
Consider this story :
Within a couple of weeks, Schonfeld, then a 46-year-old interior designer, got quickly and dramatically better, able once again to care for herself and her husband and daughter, no longer so convinced of her own worthlessness that she'd consider killing herself. For the next two months, she came back weekly for more interviews and tests and EEGs. And by the end of the study, Schonfeld seemed to be yet another person who owed a nearly miraculous recovery to the new generation of antidepressants -- in this case, venlafaxine, better known as Effexor.
A miracle drug? Not quite, she was on the placebo.
Wednesday, September 9, 2009
Seniority pay
In the course of arguing here and here for merit pay for teachers Yglesias dismisses the usual seniority based pay scales for teachers as an ineffective version of merit pay (because merit and seniority are not strongly related). But I don't think this is the main argument for seniority pay.
Research has shown people's happiness depends more on whether their condition is improving or deteriorating than on its absolute level. Seniority based pay systems take advantage of this to increase worker satisfaction. Compare a pay scale that rises from $40000 to $80000 over the course of a 30 year career to one than is a flat $60000 independent of seniority. In the seniority based system workers will get annual raises of about 2.3% (in addition to any increases in general pay levels). So their pay will go up a little every year increasing satisfaction. Unions like this as it makes the contracts they negotiate appear better than they actually are.
Of course seniority pay has disadvantages too. It requires workers to trust their employers to stay in business and not to lay off their older workers. So it is especially attractive for jobs like teacher where these aren't major worries. I doubt it will be easy to get rid of.
Research has shown people's happiness depends more on whether their condition is improving or deteriorating than on its absolute level. Seniority based pay systems take advantage of this to increase worker satisfaction. Compare a pay scale that rises from $40000 to $80000 over the course of a 30 year career to one than is a flat $60000 independent of seniority. In the seniority based system workers will get annual raises of about 2.3% (in addition to any increases in general pay levels). So their pay will go up a little every year increasing satisfaction. Unions like this as it makes the contracts they negotiate appear better than they actually are.
Of course seniority pay has disadvantages too. It requires workers to trust their employers to stay in business and not to lay off their older workers. So it is especially attractive for jobs like teacher where these aren't major worries. I doubt it will be easy to get rid of.
Tuesday, September 1, 2009
Moby Dick
Matthew Yglesias and Kevin Drum disagree about Moby Dick . Yglesias:
All that said, I love Moby Dick. Every American should read Moby Dick, it’s our great national epic and you can’t understand the country without it.
Drum:
I read Moby Dick a couple of months ago. I didn't care for it. I'll spare you the details since I'd just be opening myself up to quite justified charges of philistinism, and who needs that? But I will say this: I don't feel like I understand our country any better for having read it. ...
I have read Moby Dick but I don't remember anything much about it except that it was long and boring. So I agree with Drum.
As for requiring kids to read it, in my opinion this is wrong for anything less than a specialized college level course. Forcing students to read books like this seems like a variant of the theory that the worse a medicine tastes the better it must be for you.
All that said, I love Moby Dick. Every American should read Moby Dick, it’s our great national epic and you can’t understand the country without it.
Drum:
I read Moby Dick a couple of months ago. I didn't care for it. I'll spare you the details since I'd just be opening myself up to quite justified charges of philistinism, and who needs that? But I will say this: I don't feel like I understand our country any better for having read it. ...
I have read Moby Dick but I don't remember anything much about it except that it was long and boring. So I agree with Drum.
As for requiring kids to read it, in my opinion this is wrong for anything less than a specialized college level course. Forcing students to read books like this seems like a variant of the theory that the worse a medicine tastes the better it must be for you.
Sunday, August 30, 2009
Teachers
I recently blogged about Steven Brill's rubber room article in the New Yorker. Brill mentions in passing a study that purportedly showed that there are important differences in teacher effectiveness.
... A study of the Los Angeles public schools published in 2006 by the Brookings Institution concluded that “having a top-quartile teacher rather than a bottom-quartile teacher four years in a row would be enough to close the black-white test score gap.” ...
The study in question appears to be Identifying Effective Teachers Using Performance on the Job (pdf file) by Gordon, Kane and Staiger.
Briefly the authors construct a model for predicting student performance on standardized assessment tests at the end of the school year based on their performance on similar tests the previous year and some other factors such as sex, race, English language ability etc. The models implicitly assume the students will be taught by an average teacher. They then compare the actual results with the predicted results and assert the difference averaged over the students in a class reflects in substantial part differences in teacher effectiveness (relative to an average teacher). In particular teachers ranked high based on the first two years of their teaching career will perform noticeably better (compared to teachers ranked low) in their third year of teaching (based on how well their classes test at the end of the year relative to the results predicted for an average teacher).
The authors go on to make some policy recommendations. They note that although teachers are generally subject to a probationary period of 2-3 years at the beginning of their career with a school district before they are given tenure (and become almost impossible to fire) it is rare for a teacher to be denied tenure. They recommend ranking probationary teachers based in part on their methods and presumptively denying tenure to candidates in the bottom quartile. They make some rather extravagant predictions of social benefits from adopting this policy nationally based on some rather heroic assumptions.
An obvious question about these results is how long the improved student performance lasts. It is fairly common for short term gains to disappear in the long run. Unfortunately according to a later paper, Estimating Teacher Impacts on Student Achievement: An Experimental Evaluation (pdf file) by Kane and Steiger the effects quickly dissipate.
... In both the experimental and non-experimental data, we found that teacher effects faded out by roughly 50 percent per year in the two years following teacher assignment.
So I guess I may need to modify my earlier claim that "teachers don't matter much" to "teachers don't matter much in the long run".
I have some other criticisms of the earlier paper but if the gains don't persist they aren't very important even if they are real.
... A study of the Los Angeles public schools published in 2006 by the Brookings Institution concluded that “having a top-quartile teacher rather than a bottom-quartile teacher four years in a row would be enough to close the black-white test score gap.” ...
The study in question appears to be Identifying Effective Teachers Using Performance on the Job (pdf file) by Gordon, Kane and Staiger.
Briefly the authors construct a model for predicting student performance on standardized assessment tests at the end of the school year based on their performance on similar tests the previous year and some other factors such as sex, race, English language ability etc. The models implicitly assume the students will be taught by an average teacher. They then compare the actual results with the predicted results and assert the difference averaged over the students in a class reflects in substantial part differences in teacher effectiveness (relative to an average teacher). In particular teachers ranked high based on the first two years of their teaching career will perform noticeably better (compared to teachers ranked low) in their third year of teaching (based on how well their classes test at the end of the year relative to the results predicted for an average teacher).
The authors go on to make some policy recommendations. They note that although teachers are generally subject to a probationary period of 2-3 years at the beginning of their career with a school district before they are given tenure (and become almost impossible to fire) it is rare for a teacher to be denied tenure. They recommend ranking probationary teachers based in part on their methods and presumptively denying tenure to candidates in the bottom quartile. They make some rather extravagant predictions of social benefits from adopting this policy nationally based on some rather heroic assumptions.
An obvious question about these results is how long the improved student performance lasts. It is fairly common for short term gains to disappear in the long run. Unfortunately according to a later paper, Estimating Teacher Impacts on Student Achievement: An Experimental Evaluation (pdf file) by Kane and Steiger the effects quickly dissipate.
... In both the experimental and non-experimental data, we found that teacher effects faded out by roughly 50 percent per year in the two years following teacher assignment.
So I guess I may need to modify my earlier claim that "teachers don't matter much" to "teachers don't matter much in the long run".
I have some other criticisms of the earlier paper but if the gains don't persist they aren't very important even if they are real.
Thursday, August 27, 2009
Rubber rooms
Steven Brill has an article about that New York City institution, the rubber room, which has attracted some attention among bloggers. Rubber rooms arose because firing teachers is an extremely lengthy and difficult process (because of arbitration provisions in their union contract). But they can assigned to rooms where they sit and do nothing (with full pay and benefits) while their arbitration hearings drag on year after year. This is done when the school administration thinks it is necessary to remove a teacher from contact with children. These assignment rooms became known as "rubber rooms" . This process provides a ready supply of horror stories about teachers collecting for pay for years after instances of extreme misconduct. Steven Brill is the latest writer to mine this supply.
On the narrow point I agree with the critics, this process is indefensible and should be changed. I would suggest a no-fault termination system in which the administration could fire anyone with payment of say 2 years salary as severance. However it is not really that important in the whole scheme of things. 600 rubber roomer teachers out of 89000 is less than 1%. So just budgeting for this like you would for sick days is going to increase your costs by less than 1%. Not good, but eliminating it is not going to drastically improve school performance.
Brill suggests the real problem is that the firing process is so onerous that it is generally only used for misconduct and merely incompetent teachers stick around forever. My view is that teachers don't matter much so it is not all that important to get rid of incompetent ones.
On the narrow point I agree with the critics, this process is indefensible and should be changed. I would suggest a no-fault termination system in which the administration could fire anyone with payment of say 2 years salary as severance. However it is not really that important in the whole scheme of things. 600 rubber roomer teachers out of 89000 is less than 1%. So just budgeting for this like you would for sick days is going to increase your costs by less than 1%. Not good, but eliminating it is not going to drastically improve school performance.
Brill suggests the real problem is that the firing process is so onerous that it is generally only used for misconduct and merely incompetent teachers stick around forever. My view is that teachers don't matter much so it is not all that important to get rid of incompetent ones.
Sunday, May 31, 2009
Bang for the buck
In the course of this post about a recent change in how state universities in Texas admit students, Matthew Yglesias states:
... The marginal dollar of either the taxpayer or the charitable donor will do a lot more for society when spent on people who aren't already the best students.
It is hard to understand how anyone could actually believe this. Since good students learn new material faster and easier (and retain it longer) it is cheaper (and therefore more cost effective) to raise them to any given level of proficiency. Society would not be better off if the dumb students went to college and the dumbest went on to graduate school.
Liberals are free to argue for equality over efficiency but they should not make silly claims in the process.
... The marginal dollar of either the taxpayer or the charitable donor will do a lot more for society when spent on people who aren't already the best students.
It is hard to understand how anyone could actually believe this. Since good students learn new material faster and easier (and retain it longer) it is cheaper (and therefore more cost effective) to raise them to any given level of proficiency. Society would not be better off if the dumb students went to college and the dumbest went on to graduate school.
Liberals are free to argue for equality over efficiency but they should not make silly claims in the process.
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