Teachers’ Unions and Test Scores

I keep hearing the claim that the five states that do not allow collective bargaining for teachers have the lowest standardized test scores in the country.  If this were true, it would be worth investigating the connection between teacher unionization and student performance, only it’s not.  As Politifact documents here, the claim is false.

Wisconsin students may fare better than the five non-union teacher states, but the latter states do not have the lowest scores in the country, as had been claimed by the Wisconsin Democratic Party, among others.  For a fair comparison, it’s also important to consider participation rates.  Wisconsin high school students scored very high on the SATs in 2010, for example, but only 4 percent of students took the test, and these students are likely to be among the best in the state.  Comparing Wisconsin’s SAT scores with those of states where half to three-quarters of eligible students take the test is problematic.  It’s not an apples-to-apples comparison and does not tell us much about the comparative performance of public school systems.

Politifact Wisconsin has more on the various claims and counter-claims being made about the standoff between Gov. Walker and public employee unions.

UPDATE: Politifact’s analysis of ACT scores was based on 2009 data. It turns out that in 2010 non-unionized Virginia had higher ACT scores than unionized Wisconsin (data here), although a significantly smaller percentage of Virginia students took the test.