The Wisconsin protests have predictably spurred a great deal of information-seeking, with union supporters and opponents alike searching for evidence that supports their cases. One of the most prevalent topics over the past week or so is the effect of teacher collective bargaining on student test scores. As a result, a couple of our previous posts have been shared widely. The first (also republished here) compares NAEP scores in states that allow binding teacher contracts with those in states that do not (or have only one or two); the second, follow-up post offers some additional, multivariate analysis.
Although it is true that the first post (which was at least partially satirical - see the last few sentences) shows that states without binding contracts are among the lowest-performing in the nation, I want to clear something up: As I noted in both posts, neither the data nor my argument offer any conclusive proof that teacher contracts act to increase student test scores. The intention of those posts was to address the age-old counter claim – that teacher contracts are somehow injurious to student achievement – and to provide very tentative evidence that the contracts appear to have little discernible impact either way (which is what the follow-up post, using state-level models that controlled for basic student characteristics, indicated, along with the requisite caveats).
This speaks directly to those who seek to blame unions for poor achievement in the U.S. - if union contracts were in fact a major contributing cause of low test performance, it might be reasonable to expect to find at least some clear differences between states that did and did not allow them. Although my analysis was extremely limited, I found no such evidence.
But this also applies to those who have been claiming recently – many in the Wisconsin context – that teacher bargaining clearly improves these outcomes.