Yesterday I argued that Diane Ravitch is wrong to say that Massachusetts proves teachers unions to be a non-factor in education reform. Diane responded here. Now it's Jay Greene's turn (from this comment):
Diane Ravitch's suggestion that critics point to a state or district that has done well without teacher unions to counter her example of MA that has done well with unions is a horrible way to determine the truth on this matter. Many factors influence student achievement, so isolating the effect of teacher unions would require a rigorous social science research design that could identify the influence of unionization independent of other factors.Rather than point to a state or district, which proves nothing, I would point people to a rigorous study by Caroline Hoxby in a leading economics journal. The abstract states: "I find that teachers' unions increase school inputs but reduce productivity sufficiently to have a negative overall effect on student performance."
See Caroline Minter Hoxby, "How Teachers' Unions Affect Education Production," The Quarterly Journal of Economics, Vol. 111, No. 3 (Aug., 1996), pp. 671-718
If Diane Ravitch wants to convince readers that the unions do nothing to lower academic achievement I would challenge her to point to a rigorous piece of social science research that supports her argument rather than spin a story about MA without any controls for extraneous factors.
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(Editor's note: To read the study mentioned above, click here. The third search result leads to the full PDF.)
