Comments on the Postrel Article on Teacher Quality

The dynamist herself is popularizing the academic work of Sean P. Corcoran, who is now a prof. at California State University, Sacramento. His paper is here. The article states, "Research over the last decade has demonstrated that teachers' aptitude test scores, particularly their verbal scores, are the best predictors of how their students will achieve." Its nice that research validates this intuitively obvious assumption. Teachers convey a lot of information verbally, and the most complex information is often passed on verbally. The better the teacher is verbally, is stands to reason, the better job of passing along information. The research confirms this.

The article conforms that teacher quality has declines as women have been liberated from narrow career choices in nursing and teaching. However, the slip is less pronounced than has been assumed, being largely confined to the best and brightest women, who have the most choices about where to sell their abilities in a much larger marketplace. However, while we attract fewer of the brightest women in the teaching profession, we also recruit fewer of the low aptitude women. Teaching demand has fallen since the 50's and 60's when the Baby Boom had to be schooled. It reached a nadir in the 80's in a gap between the children of boomers and the grandchildren. In fact my own research shows that the vast majority of teachers were certified in the 70's and 90's. Its hard to find a teacher certified in the 80's, because the large number of the 70's to teach my generation left plenty of teachers in the system even as enrollments fell. Not only did hiring fall off, but teacher salaries fell in real terms in the early 80's. Aside from this dip they are stable in real teams over the past 40 years.

So, as one would expect from a free market unencumbered by gender bias inefficiency, the best and brightest are finding better employment elsewhere, the smaller demand has eliminated the need to scrape the bottom of the barrel. So, the average is pretty stable, since the broad middle seems much less effected. The decline, I mentioned was very slight, being confined to the top, and compensated for at the bottom.

The second part of the article explains what specific market forces are at work here. After, all given a free market, teaching might still be better than the alternatives. Given the needs of childcare, for instance, teachers share a similar schedule as their children, often arriving home shortly after the children do if they ride the bus. Children close enough to walk can get home almost an hour earlier than teaching mothers. This is still and hour or more better than 9-5 moms. So, given the notion that teaching offers some advantages, we have to look to the overall balance of the opportunity, and as we should expect, the opportunities for the top in a free market exist at a greater range. A potential teacher with the best scores will tend to seek the most free markets because the reward for her relative advantage will be most accurate. However, just as the market for women's employment became more free, the market for the supply of teachers became less free as unionization and pay-equity laws regulated the market. This constraint at the top of potential incomes are the downside that caused the best women to avoid teaching. They were not getting rewarded for their superior ability in teaching as they were in other fields. Apparently the superior compensation outweighed the other advantages of teaching as a profession, and so the brain drain.

See the paper by Caroline M. Hoxby and Andrew Leighon on incomes and teacher recruitment here. They conclude that 80% of the cause for high performing women to avoid teaching has been the compression of wages in teaching that fail to compensate them as they are able to be in the free market.

Postrel concludes, "In hiring teachers, we get what we pay for: average quality at average wages."