Teachers: Much More Than You Wanted To Know

Teachers: Much More Than You Wanted To Know | Slate Star Codex: "Newspapers report that having a better teacher for even a single grade (for example, a better fourth-grade teacher) can improve a child’s lifetime earning prospects by $80,000. Meanwhile, behavioral genetics studies suggest that a child’s parents have minimal (non-genetic) impact on their future earnings. So one year with your fourth-grade teacher making you learn fractions has vast effects on your prospects, but twenty-odd years with your parents shaping you at every moment doesn’t? Huh? I decided to try to figure this out by looking into the research on teacher effectiveness more closely.

This turned out to be a mistake."



'via Blog this'

• Newspapers report that having a better teacher for even a single grade (for example, a better fourth-grade teacher) can improve a child’s lifetime earning prospects by $80,000. Meanwhile, behavioral genetics studies suggest that a child’s parents have minimal (non-genetic) impact on their future earnings. So one year with your fourth-grade teacher making you learn fractions has vast effects on your prospects, but twenty-odd years with your parents shaping you at every moment doesn’t? Huh? I decided to try to figure this out by looking into the research on teacher effectiveness more closely. This turned out to be a mistake.
• So put more simply – on average, individual students’ level of ability grit is what makes the difference. Good schools and teachers may push that a little higher, and bad ones bring it a little lower, but they generally can’t work miracles.
• Teachers account for about 10% of variance in student test scores, it’s hard to predict which teachers do better by their characteristics alone, and schools account for a little more but that might be confounded
• Add like fifty layers of incomprehensible statistics and this is the basic idea behind VAM (value-added modeling)... A claim like “VAM accurately predicts test scores” is kind of circular, since test scores are what we used to determine VAM... The answer is – they decay pretty fast. Jacob, Lefgren and Sims find that only 25% of gains carry on to the next year, and only 15% to the year after that... I expected teachers’ groups and education specialists to be pushing all the positive results. After all, what could be better for them than solid statistical proof that good teachers are super valuable? In fact, these groups are the strongest opponents of the above studies ... It’s always fun to watch rancorous academic dramas from the outside, and the drama around VAM is really a level above anything else I’ve ever seen....Historian/researcher Diane Ravitch doesn’t have quite as cute an aesthetic, but she writes things like: VAM is Junk Science
• I’ve been linking to recently suggesting that excessively early school starting ages seem to produce an ADHD-like pattern of bad behavior and later-life bad effects, which I was vaguely willing to attribute to overchallenging kids’ brains too early while they’re still developing
• n summary: teacher quality probably explains 10% of the variation in same-year test scores, which corresponds to a +1 SD better teacher causing a +0.1 SD student test score improvement, which isn’t that much. This decays quickly with time and is probably disappears entirely after four or five years, though there may also be small lingering effects. It’s hard to rule out the possibility that other factors, like endogenous sorting of students, or students’ genetic potential, contributes to this as an artifact, and most people agree that these sorts of scores combine both signal and noise. For some reason, even though teachers’ effects on test scores decay very quickly, studies have shown that they have significant impact on earning as much as 20 or 25 years later, so much so that kindergarten teacher quality can predict thousands of dollars of difference in adult income. This seemingly unbelievable finding has been replicated in quasi-experiments and even in real experiments and is difficult to banish. Since it does not happen through standardized test scores, the most likely explanation is that it involves non-cognitive factors like behavior. I really don’t know whether to believe this and right now I say 50-50 odds that this is a real effect or not – mostly based on low priors rather than on any weakness of the studies themselves. I don’t understand this field very well and place low confidence in anything I have to say about it
•  there’s strong evidence that parents have relatively little non-genetic impact on their childrens’ life outcomes, but now we’re saying that even a kindergarten teacher they only see for a year does have such an impact? And what’s more, it’s not even in the kindergarten teacher’s unique area of comparative advantage (teaching academic subjects), but in the domain of behavioral problems, something that parents have like one zillion times more exposure to and power over?