At last, a key missing piece of Milwaukee’s school voucher program – an evaluation – may fall into place. No, the circumstances are not ideal. The main drawback is lack of state sponsorship, due to Gov. Jim Doyle’s refusal to cooperate. But a research institute has stepped forward, offering to tap foundations to fund the study – the second-best way to go. The team also includes John Witte, a University of Wisconsin-Madison professor who conducted evaluations in the early years of the program, before its expansion into religious schools.