The $300,000 Kindergarten Teacher

The $300,000 Kindergarten Teacher

       Image via Education Week

How important is a good Kindergarten teacher?  When measured in terms of lasting impact on test scores, the answer is “not very”; gains on standardized test scores actually fade over the subsequent elementary years.   By grade 8 or so, the impact fades to the point that those children look about like their peers who were not placed with a good teacher. That was according to an experiment in Tennessee designed to measure the academic impact of Kindergarten placement on children in low-income schools. This is not an unusual finding:  a similar study on Pre-K found that by grade 3, the effect of preschool on test scores had faded.


Raj Chetty, an economist at Harvard, wondered if the researchers hadn’t studied the effects on students long enough to get a true picture of the impact that might be occurring.  He took the Tennessee data on Kindergarten placement and correlated it with tax records and other documentation and found some really startling results:

  • Children assigned to good classrooms (experienced, capable teachers, smaller class sizes) were earning 3% more than those from not-so-good classrooms.  This amounted to a $300,000 increase in total earnings over the student’s career.
  • Students in smaller classes (+/- 15 kids) were 6.7% more likely to attend college before age 25 than students in larger classes.
  • Students in smaller classes with experienced teachers were more likely to have a job with a 401k plan, which the researchers used as a proxy for a good, higher-paying job.
  • Students were more likely to get married, own a home, and live in neighborhoods that were safer and more economically stable.
  • The effects were especially marked for African American boys and those who entered with lower scores.
  • Results suggest that high quality Kindergarten classrooms may build non-cognitive skills that have returns in the labor market but do not improve performance on standardized tests.

I have written about “soft skills” in this space before:  those skills taught in school that are not really measurable on tests but that have an impact that may last well into adulthood.  What is fascinating, is that both studies I have cited have measured the impact of very early childhood education — Preschool and Kindergarten, respectively.

A few caveats:

  • Researchers can’t really say what teacher characteristics were responsible for this effect.  What they can say is that it’s not race, college degree held, or career progress.  Experience was the only measurable characteristic that predicted teacher quality.
  • They also noted that it was difficult (nearly impossible) to separate some variables in the research beyond class size and teacher experience, notably the effect of the entire class — the mix of children, genders, races, personalities, abilities — on results.  They conceded that this may have some impact on results, but they can’t quantify it precisely.  This doesn’t bother me too much:  districts can’t exclude kids anyway so it’s comforting that the variables we can control — class size and teacher experience — make a difference.
  • There was a tendency for the mix of kids in a class to affect test scores (but not necessarily long term outcomes), where an increase of kids in poverty in any given class resulted in lower scores.  That’s as good an argument against tracking as you’ll find. Balancing classrooms in early childhood education is also important.

The research suggests a couple of things:

What happens before age 7 really matters.  Good teachers and smaller class sizes are critical for early childhood education.  It wouldn’t be a stretch to say that districts need to focus resources in the Pre-K-Grade 2 band with the most experienced teachers in classrooms with fewer kids.

We are playing the long game.  These results aren’t necessarily going to boost test scores for very long, but education isn’t a simple process of inputs in, results out.  Children aren’t machines.

I love it when economists look at educational factors; the perspective here is very enlightening.  I have yet to encounter a district whose mission statement doesn’t include something along the lines of “helping kids be good citizens of the world”; Chetty’s research seems to indicate that this is how we do that.

You can read the entire report on the economic impact of Kindergarten placement on Raj Chetty’s website.


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