The District of Columbia’s other City Council/School Board (also known as Congress) is currently considering a bill that would give some District families up to $7500 in vouchers to pay for all or part of their child’s private school tuition. The five-year plan would be the federal government’s first test of the voucher concept. Except that the test doesn’t have a valid final exam.

The bill requires the Department of Education to conduct some kind of evaluation of the program and you might think that would mean giving the same end of year test to the voucher students as is given to the students in the public schools. You would be wrong. DOE "officials do not want to require private schools to administer the same standardized test given by D.C. public schools because it would be an unnecessary burden".

So maybe we could work out some way of comparing the results of the tests given by private schools with those given by public schools.

Not all private schools in the District use tests that can be compared with the Stanford 9. Among a handful of private schools that were asked about their testing policy, Rock Creek International uses a homemade test, and the Sheridan School does not have a schoolwide achievement test.

Researchers who have studied the effectiveness of vouchers said that comparing the results of the Stanford 9 and Terra Nova tests would yield workable, but not perfect, comparisons. But comparing the Stanford 9 results with a patchwork of other tests would be problematic, they said.

"It’s going to be a lot harder if what we have is some kids taking the Terra Nova, some kids taking the Stanford 9, some kids taking the Iowa Test of Basic Skills and some kids taking something you’ve never heard of," said Caroline Hoxby, a professor of economics at Harvard University who has studied vouchers and written favorably about them.

As tricky as the process of evaluating student progress can be, there is another assessment piece also missing from this experiment. Voucher supporters frequently assert that the competition created by such programs will in turn improve the public schools. Where is the evaluation component to demonstrate the validity of that claim?