20 February 2011

Unions and Student Achievement

It's going around Facebook: five states prohibit collective bargaining for teachers, and their students rank lowest in the nation in average SAT scores. But is it true?

Well, no.

Here's a map from the National Council on Teacher Equality that shows the five states that prohibit teachers from unionizing. The states: Texas, Georgia, South and North Carolina, and Virginia.

The data:

According to a table posted here, the five lowest states for combined scores in all three subtests are Maine, Hawaii, South Carolina, Georgia, and New York, with Texas coming in at #6.

(I'm using the total of scores on all three subtests for this ranking; the website only provides the scores broken down by subtest, so I copied the data into an Excel spreadsheet to do the addition and the comparisons.)

However, this data is skewed by the percentage of students who take the test; more takers seem to translated to lower scores. Maine requires all juniors to take the SAT; 90 percent of students in fact take it; and Maine has the lowest average scores in the nation. Next on the list, with 85 percent of students taking the SAT, is New York, which also falls into the five-lowest group.

But South Carolina, Georgia, and Texas have lower percentages of students taking the SAT -- 67, 71, and 51 percent, respectively -- so on the assumption that where better students self-select to take the SAT, the averages should be higher. So the fact that those three states rank 3rd, 4th, and 6th should still prompt a hard look at educational policies, and how they might be affecting achievement.

(How about Virginia and North Carolina? 12th and 8th from the bottom, respectively, with 63 and 68 percent of students taking the test.)

Update: I looked up ACT scores, and it's not true for those, either. I was wondering, though, if Texas is an ACT state and that's why such a low percentage of students take the SAT -- but only 33 percent of Texas students take that test. Is this the result of former Governor Bush's No Child Left Behind policies?