I thought about checking the data myself to test the claim. I went to the OSPI web site to review the student achievement (MSP pass rate) data for districts of various sizes. But as I did so, I realized that I had no way of determining, from that data, how the performance of low-achieving students had changed. Yes, I could compare the 2013 5th grade pass rates with the 2012 4th grade pass rates, but that wouldn't allow me to determine which of the former 4th graders accounted for which of the 5th grade scores. I couldn't parse out the change for the low performing students from a previous year.
That got me wondering how Representative Pettigrew did it. Actually, it got me suspecting that he didn't. I don't think he has any data to support his claim. That means that Mr. Pettigrew is likely proposing an extreme and expensive action - splitting Seattle Public Schools into two districts - to achieve a specific purpose without any evidence whatsoever that the action will, in fact, achieve the purpose. That would be pretty messed up.
So let's see the data, Mr. Pettigrew. Show us why you believe that smaller school districts improve the performance of low-achieving students. Please, please, please, show us the basis for this claim. Because, if you don't have any data to support this claim, then why are you making the claim and why are you proposing this action?