There's been a factoid making the rounds during the Wisconsin union standoff that you may have seen. I'm not sure what the ultimate source of the factoid is, but here's the meat of it as reiterated by a blogger for The Economist:
Only 5 states do not have collective bargaining for educators and have deemed it illegal. Those states and their ranking on ACT/SAT scores are as follows:
South Carolina – 50th
North Carolina – 49th
Georgia – 48th
Texas – 47th
Virginia – 44th
If you are wondering, Wisconsin, with its collective bargaining for teachers, is ranked 2nd in the country.
Now, aside from the factoid, if true, providing no real insight into whether collective bargaining is good or bad for education -- there are myriad variables at work other than collective bargaining, none of which does this control for -- but the factoid itself is highly dubious. Again, it is hard to find the original source for this, but I looked up 2009 ACT and SAT state rankings, and at the very least it seems highly unlikely that Virginia ranks 44th out of all states. According to the ACT ranking, for instance, Virginia places 22nd, and on the SAT (assuming the linked to list is accurate -- I'm doing this fast), it ranked 33rd. It's hard to see how those would be combined for a 44th place overall finish.
How about the Wisconsin second place-finish? Well, that is accurate for the SAT, but notably only 5 percent of Wisconsin students took the SAT -- a negligible rate. On the ACT, which is the main test taken in the Badger State, Wisconsin finished 13th -- not bad, but hardly great.
So what does this tell you? Not that collective bargaining is educationally good or bad -- like I said, you just can't get there from here -- but that you have to be very careful about your sources of information. Unfortunately, that seems especially true when you're dealing with education.