Teacher effects – At the margin?

As mentioned in my previous post, the results of the AP Statistics exam raised again in my mind the question of “how important is the teacher in the results of his/her students on the AP Exam?” The reason for this question is that I now have taught AP Statistics for 6 years and the results of my classes vary from year to year. Even though I got more familiar with the material, the average class scores of my students go up and down despite my having gained more experience and hopefully being a better teacher.

First I should qualify that, in my book at least, results are defined as (a) what percentage of my kids have passed the exam and (b) what percentage have gotten 4s or 5s on the exam. If one acknowledges another dimension of success – number of students taking the AP Stats course – then I am successful, the number has doubled. However, as I have argued in the previous post, I am more interested in quality than in quantity.

It may well be that as the number of students taking the class increases, the chances are the average performance will go down. After all, if AP is considered at the top of the pyramid in terms of challenging courses, there are only a limited number of students who are prepared or capable of meeting the challenge.

The other side of this argument is that “it is up to you Ms./Mr. teacher to ‘raise’ the unprepared so they too can meet the challenge”. I think this is a very simplistic argument that holds little or no water. Students come to class carrying a lot of different baggage. This year, in AP Stats, they told me of divorces, parents losing jobs, accidents and illness and that does not take into account the usual teenage angst about college admissions, relationships and others.

In addition to the personal there is the academic baggage. Some students did not have the mathematical maturity that others had by taking another year of math (see my previous post). Some had been successful in school without being challenged academically. Some were taking 5 AP courses and were overwhelmed by the demands on them.

To believe that teachers are inspirational miracle-workers that can do the “Stand and Deliver”  thing year after year is nonsense. After all, Jaime Escalante was not able to duplicate his achievement in Sacramento. There are too many confounding variables in students, administrators and teachers themselves to expect identically great performance year after year.

This leads me to conclude that teacher effects are somewhat marginal. Serious students, well prepared and with good work ethic will probably do well even if the teacher is below par. Poor students, those who give up easily despite all encouragements, those students are likely not to do well even with an above average teacher.

Therefore the game is played at the margin. When a student (who did not pass the AP Exam) writes “Even though this was one of the hardest classes I have ever taken I am really glad I did…. I feel like you have really prepared me for college and I know I would’ve regretted not taking this class!” – then you know you’ve hit a winner and average class performance… well we teach the kids that the mean is only one measure that characterizes the distribution.


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