During the much-balley-hooed interview with the Milwaukee Journal Sentinel about vouchers, Sen. Barack Obama expressed concern that there had been no long-range study of the city’s voucher program.

Well, now there is, or at least the beginning of one.

Though the results are preliminary, there are some interesting tidbits in the University of Arkansas study (the first year of a planned five-year study), which you can check out for yourself. The summary is here, or a complete menu of options here.

First, vouchers haven’t made a huge difference in student performance, and in fact, results are mixed as to whether voucher students perform better on standardized tests—but it’s early, the researchers emphasize. The report is based on 2006-07 data, and this will serve as the baseline for comparing future years.

Second, parents in both the traditional schools and vouchers schools have high levels of satisfaction with their schools. And third, voucher schools don’t appear to be skimming the best students off the top.