Former Minneapolis Superintendent Bernadeia Johnson left the position recently in part to care for older relatives, but also due to waning school board support. After about four years on the job, she stepped down well before her contract was to come up for renewal.

In St. Paul, Superintendent Valeria Silva appears to have her elected board's backing — at least for now. She survived a review last year, and her current contract (signed in 2012) will expire in December.

In both districts, struggling students are doing equally poorly — with the exception of graduation rates. And if school chiefs and elected boards should be judged based on how well all kids are learning, then both leave something to be desired. More than half of the students in both districts were not deemed proficient in reading and math on the most recent statewide tests.

Three to four years is the average tenure of an American big-city school chief. So it's a good juncture at which to review the record and consider what needs to happen in the future — especially in light of growing public disappointment over public school performance.

That disenchantment is reflected in enrollment figures. St. Paul and Minneapolis district leaders predicted substantial enrollment increases that didn't materialize. Both have lost thousands of students to charters and other alternative programs for a variety of reasons, including disruptive student behavior.

Both district administrations have addressed problems with suspensions and expulsions and made worthy efforts to keep more children in school. In the process, though, they're risking losing good students whose families don't want their kids in poor learning environments. The districts need to explore more alternative disciplinary measures, including in-school suspensions — to help balance the needs of students who are engaged in their classwork.

St. Paul devoted time and resources to a racial-equity initiative to help staff members discuss how their biases have negative impacts on students of color. Silva says that is resulting in positive change in classrooms — though it has not yet come through in test results. But some educators have said they still need more specific strategies to work with difficult students.

Joe Nathan, director of the Center for School Change in St. Paul, says that Silva's goals have been good but that implementation has been lacking. He said teachers want and need more meaningful training to help youngsters succeed in school.

Nathan has worked with successful charter and traditional schools. He said there are good examples of how educators can work with even the most challenging school populations.

In that arena, Johnson's administration was more open to developing partnerships and working with quality programs to replicate their success. Silva took the opposite position and pulled out of backing charter programs.

An editorial writer's recent separate interviews with both superintendents highlighted the differences in their philosophies. Johnson's "shift'' speech more than a year ago set a tone for reform. She bluntly said teachers and other school staff would have to do things differently to get better results for kids. But as she was about to step down, she expressed frustration that even steps that were negotiated into union contracts were simply ignored.

During her recent state of the district speech, Silva emphasized that St. Paul schools are better off in 2015 fiscally, instructionally and technologically, and that they must do a better job of communicating changes and sharing their good news.

Both superintendents believe they have laid important groundwork for student achievement to improve. Yet there is growing impatience with poor results. Again and again, superintendents and school boards have promised that the next strategic plan would make a difference. But the results are inadequate, especially among low-income students of color.

What can be done? Both Johnson and Silva emphasize the importance of strong, united school boards and administrative teams that are unafraid to make tough decisions that work for students — no matter how unpopular they may be with constituencies inside and outside the schools. School leaders also need the ability to change course quickly when necessary to drop things that don't work. Community members and voters can help by voicing concerns, applying pressure from outside and holding leaders accountable through their votes.

Failure to do so gives ammunition to those who would dismantle urban public schools. If progress is not expedited, interest will grow in more state or mayoral control, distributing core city school operations to surrounding suburbs or creating larger regional school districts.