Supporters of the public employee unions have recently been circulating state-by-state information on collective bargaining, and then comparing it to statistics on ACT and SAT performance in the respective states. This "data" started to be passed around via Twitter and Facebook; for example, "5 states forbid collective bargaining for educators: SC, NC, GA, TX, & VA. Their national rank in ACT scores: 50th, 49th, 48th, 47th, 44th."
A friend of mine who is a public school teacher--and who is obviously closely following events in Wisconsin as well as closer to home, shared this with me, along with the claim that good ol' progressive Wisconsin ranks #1 in ACT/SAT testing. I investigated this claim, which traces back to this chart.
As it turns out, these ratings are bogus. For each state it adds the ranking for SAT scores to the ranking for ACT scores (and it's not even clear what year the data comes from), but it doesn't take into consideration the percentage of the population who take either test. The College Boards specifically warn against doing state-to-state comparisons for the SAT, because in some states all students are required to take the text, while in others only the best students do. Only 4% of Wisconsin students took the SAT in 2010, and since they tend to be the cream of the crop it's not surprising that Wisconsin does well (but third in the nation, not first). On the other hand, 69% of Wisconsin seniors took the ACT in 2010, and Wisconsin comes in 17th in terms of composite ACT scores.
A more thorough debunking of these statistics may be found here; among the revelations is the fact that the data is from 1999. The owner of this site is actually an advocate of "student organizing"; it is to his credit that he has the intellectual honesty to challenge claims that purport to back up his side of the argument.
Does collective bargaining correlate with performance by students on standardized tests? Of the five states whose students performed worst on the ACT, three--Michigan, Tennessee, and Florida--mandate collective bargaining with teachers' unions. The other two permit school districts to bargain collectively, but do not mandate it.