Effects of Good Teachers on Student Outcomes

These findings would suggest that the difference in achievement gains between having a 25th percentile teacher (a not so effective teacher) and a 75th percentile teacher (an effective teacher) is over one-third of a standard deviation (0.35) in reading and almost half a standard deviation (0.48) in mathematics. Similarly, the difference in achievement gains between having a 50th percentile teacher (an average teacher) and a 90th percentile teacher (a very effective teacher) is about one-third...

 We Take Things for Truth When They Need to Be More Thorou...

You see the problem fo obtaining facts from experience--it sounds very, very simple. You just try it and see. But man is a weak character and it turns out to be much more difficult than you think to just try it and see. For instance, you take education. Some guy comes along and he sees the way people teach mathematics. And he says, "I have a better idea. I'll make a toy computer and teach them with it." So he tries it with a group of chidlren, he hasn't got a lot of children, maybe somebody g...