The Effect of Good Teachers

The Effect of Good Teachers

How about this: the effects of a good or excellent teacher include lower teen pregnancy rates, greater college matriculation, and greater lifetime earnings as an adult.

Those facts come from a study that tracked 2.5 million students over 20 years. I don’t think we can really argue with the sample size.  The study was done by economists from Harvard and Columbia. They find that if an excellent teacher replaces an average teacher anywhere between 4th and 8th grade, the student will earn $4600 more in his or her life and be slightly more likely to attend college.

Modest right? But in a class of 25 students that is $115,000 more in the economy. Multiply that by a 30 year career and you’ve added $3.4 million. And the numbers work from worst to average as well- the same things happen when a poor teacher is removed and an average teacher added. Certainly significant, makes me want to digress to talking about rural teacher recruitment and retention.

So here’s the part that may start debate.  The researchers used “value-added” ratings to separate excellent, average, and poor teachers.  A value-added rating “measures an individual teacher’s impact on student test scores.” Yep, what they are saying is that better teachers lead to higher standardized test scores, which lead to college and earnings. The opposition would tell you that VA scores are unreliable, invalid, and unfair. That it is too difficult to measure the effect of one teacher on a class’s test scores with all the variables needed to be taken into account (poverty, ELL, SwD, maybe even prior teachers, etc.).

But VA scores are coming to NY, they are a part of the new teacher evaluation system. NYC already uses it. Check out the formula:

Crazy, right? So, what are the takeaways? I don’t think any of us doubt a good or excellent teacher has a lasting effect. I wonder if having a string of excellent teachers continues to add to the effects (earnings, college attendance, etc.). I wonder about the emphasis on standardized tests as well, especially in NY. What do you think?

Read more at The New York Times.