On April 5, Superintendent Bernadeia Johnson's periodic Leader Letter touted improved graduation rates for Minneapolis students -- the four-year graduation rate was up to a whopping 50.1 percent.

Or so she said.

But repeated Star Tribune queries to the district's communication staff for school-level details to back up the claim have so far been ignored. Among the key questions are which schools contributed most to that claimed gain, and whether the claimed 2012 rate reflects all the district's alternative schools, or just the seven big traditional high schools.

The most recent graduation information posted on the district's accountability scorecard site lists a 2012 graduation rate of 46.9 percent. That's actually the 2011 rate, lending further confusion to the matter. And it's well below the target set by the district for 2012 of 77.5 percent. But that rate was set under the old methodology for calculating grad rates.

If the district would deign to answer questions about its figures, some of this might be clarified. But despite the district listing transparency and accountability among its core values, that hasn't happened.