Jay Greene on The Imaginary Teacher Shortage

Jay Greene has a thoughtful post on the The Imaginary Teacher Shortage.  He points out several problems with merely hiring more teachers.  His column starts with:

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Last week's presidential debate revealed one area of agreement between the candidates: We need more teachers. "Let's hire another hundred thousand math and science teachers," proposed President Obama, adding that "Governor Romney doesn't think we need more teachers."

Mr. Romney quickly replied, "I reject the idea that I don't believe in great teachers or more teachers." He just opposes earmarking federal dollars for this purpose, believing instead that "every school district, every state should make that decision on their own."

Let's hope state and local officials have that discretion—and choose to shrink the teacher labor force rather than expand it. Hiring hundreds of thousands of additional teachers won't improve student achievement. It will bankrupt state and local governments, whose finances are already buckling under bloated payrolls with overly generous and grossly underfunded pension and health benefits.

For decades we have tried to boost academic outcomes by hiring more teachers, and we have essentially nothing to show for it. In 1970, public schools employed 2.06 million teachers, or one for every 22.3 students, according to the U.S. Department of Education's Digest of Education Statistics. In 2012, we have 3.27 million teachers, one for every 15.2 students.
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Jay Greene has many points about how throwing more money and telling schools they have to hire more teachers will probably not improve government schools.

Hat tip: Instapundit.