In a new analysis released today by School Choice Wisconsin, University of Minnesota sociologist Rob Warren finds that voucher students in Milwaukee graduate high school at a higher rate than students in Milwaukee Public Schools.
According to the Milwaukee Journal Sentinel’s coverage this morning:
For 2007-’08, Warren estimated the graduation rate in voucher schools to be 77%, and the graduation rate in MPS to be 65%, a difference of 12 percentage points. The information includes comparisons between seven choice schools and 23 public high schools that could provide complete data for all six years studied, and adjusted to account for an expected 5% ninth-grade retention rate in choice schools and an expected 25% ninth-grade retention rate in MPS.
And from the report’s summary we get an idea of how big that difference in graduation rate is:
As Professor Warren illustrates here, had MPS attained the same graduation rate achieved in the MPCP, an additional 3,352 students would have received diplomas between 2003 and 2008. According to the research cited in the Journal Sentinel, the annual impact from an additional 3,352 MPS graduates would include an additional $21.2 million in personal income and about $3.6 million in extra tax revenue.
Warren is careful to note that his analysis does not determine whether vouchers caused the higher graduation rate or attracted students who were more likely to graduate, but he is pretty confident that the voucher students do graduate at higher rates. the public school officials are not so convinced: “You have to take into account things like mortality, and the number of students who move to another school,” St. Aubin said.
Mortality? Is that a plausible explanation for the difference? Warren’s method is similar to earlier work that Greg, Marcus, and I have done in estimating graduation rates and while not absolutely precise is likely to be reasonably accurate. A forthcoming analysis by the School Choice Demonstration Project led by my colleague at the University of Arkansas, Pat Wolf, and with which I am involved will be able to examine this issue tracking individual students over time.
Jay P. Greene's Blog 
Jay, as I recall, back when you started challenging traditional grad rate calculations – before it was cool – you found that Washington State was hiding all its dropouts in a huge category called “dead or other.”
Was it also Washington State that wouldn’t count kids as dropouts unless they filled out a form declaring they were dropping out? Or was that a different state’s scam?
The state of Texas had dozens of student “leaver codes” only one of which was “dropped out of school.”
As it turns out “abducted by space aliens” probably got more students than “dropped out of school.”
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