Teacher Cognitive Skill Seems to Matter, Except in South Korea

Despite my tendency to drone on about charter schools, I also believe we should be spending a lot of time and energy on increasing the quality of our nation’s teaching force.

Yesterday, this study came out. The authors argue that teacher cognitive skill (as measured by adult PISA tests) is an important variable in understanding country academic performance; in their own words:

Our analysis consistently indicates that students living in the countries at the top of the PISA rankings perform better in math and reading in part because their teachers have higher numeracy and literacy skills

The methodology used is quite complex, and I don’t fully understand it, so I apologize in advance if I get things wrong below.

From the study…

Comparing Teachers from Around the World to People in Canada

The literacy skills of the lowest-performing teachers (in Italy and Russia) are similar to the literacy skills of employed Canadian adults with only a vocational degree (278 points). Teachers in Canada, the Netherlands, Norway, and Sweden have similar skills than adults with a bachelor degree (306 points). The literacy skills of the best-performing teachers (in Japan and Finland) are even higher than the skills of Canadian adults with a master or doctoral degree (314 points).

In short, the authors use comparisons to Canadian adults to demonstrate that there is a wide variety of cognitive skill in teachers across the globe.

Here’s a chart:

Screen Shot 2015-04-13 at 2.13.09 PM

Comparing Teachers to Other College Graduates In Their Home Countries

As most teachers are college graduates, it is also illuminating to compare teacher cognitive skills with the skills of all college graduates in a country (see Figure 2). While median teacher cognitive skills fall in the middle of the 25th-75th percentile skill range of cognitive skills of college graduates in most countries, teachers come from the upper part of the skill distribution in some countries (e.g., Finland and Japan) and from the lower part of the college graduate skill distribution in other countries (e.g., Poland and the Slovak Republic).

In short, teachers in some countries are near the top of cognitive performance for college graduates in their country, while teachers in other countries are closer to the bottom.

Here’s a chart:

Screen Shot 2015-04-13 at 2.12.14 PM

Korean Culture > Korean Teachers

I thought this was of interest: Korean students dramatically outperform what you would expect given their teacher quality.

Screen Shot 2015-04-13 at 2.16.06 PM

Culture matters.

How Much More Would USA Students Achieve if Our Teachers Had as Much Cognitive Skill as Teachers in Finland?

The U.S. would be expected to improve by roughly 0.55 SD in student math achievement… Of course, these are long-run impacts since they presume that the quality of students’ teachers in the first ten grades would improve to the level of Finland – something that would take some time and effort to realize.

This is a very large effect.

Does More Money Get You Better Teachers?

In other words, while making it clear that a more skilled teaching force will require higher salaries, the evidence says nothing about either how salaries should be structured or the responsiveness of teachers to higher salary offers.

It’s probably necessary but not sufficient.

Who Do Better Teachers Help the Most?

Our results suggest that the benefits of better cognitive skills of teachers mainly accrue to students with low socioeconomic background, while parental skills are more important for students with high socioeconomic background.

What is Optimal for a Country?

The authors did not really address the issue of cross-sector trade-offs. Presumably, a nation could boost its test scores by ensuring that their schools were saturated with teachers in high cognitive skill.

I imagine that, at some point however, this a diminishing returns to teacher cognitive skill. Additionally, some industries are probably made worse off by high cognitive skill college graduates going into teaching.

I wonder how you might try and model out what the sweet spot is.

So What Should We Do?

Two routes could get us to higher performing teachers: regulation or deregulation. I’ve written about this before. In certain states (New York) and countries (Finland), increasing the rigor of credentialing seems to have increased teacher cognitive skill.

In New Orleans, deregulation seems to have had the same effect.

One other twist: it’s unclear how economic shifts might affect labor supply, as well as how this factors into how much we would need to pay teachers to get a higher-quality workforce.

I think this is an area that’s right for experimentation.

Potentially, a combination of rigorous credentialing coupled with school deregulation could be the best way forward…. but much remains unknown.

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