As Minnesotans start selecting candidates for governor and the Legislature, here's good news about our public schools, followed by some questions arising from that information that we might ask.

Minnesota high school graduation rates are increasing and graduation gaps are closing. Meanwhile, there is a decline in the percentage of public high school graduates who are taking "developmental" courses on entering Minnesota's colleges and universities (also called "remedial" courses).

The National Center for Education Statistics shows that Minnesota's four-year high school graduation rates increased from 2011 to 2016 overall and for every student group. Equally important, gaps between students of different races are narrowing.

Minnesota's four-year high school graduation rates improved from 2011 to 2016 as follows: African-American, from 49 percent to 65 percent; American Indian, 42 percent to 53 percent; Asian-American, 72 percent to 84 percent; Hispanic, 51 percent to 65 percent; white, 84 percent to 87 percent.

Detailed information about four-year "adjusted cohort high school graduation rates" is available for 2011 and for 2015-16. These figures show that Minnesota ranks slightly below national high school graduation averages: 84 percent nationally and 82 percent in Minnesota for 2016.

But graduating from high school isn't enough. Some educators and critics report that graduation rates increased in part because high schools are pushing students through, even if they have weak skills.

So a Minnesota Office of Higher Education report is especially encouraging. It found a decreasing percentage of high school graduates taking remedial courses in college: from 28 percent for 2010 graduates to 23 percent for 2014 graduates. Preliminary figures for 2015 graduates show another reduction, to 21 percent. Students taking remedial courses are less likely to graduate.

Students and schools are more complex than just a few numbers. But these changes are heartening.

Although it's impossible to explain fully why this progress took place, here are several research-based contributing factors.

The number of low-income Minnesota youngsters participating in early-childhood programs has grown dramatically. For example, Head Start enrollment grew from about 9,000 in 1992 to more than 14,000 in 2003. This helped increase graduation rates 12 years later.

Minnesota Department of Education research shows that participation, from 2010 to 2015, of low-income students and students of color increased by 50 to 100 percent in dual-credit (high school/college) programs such as College in the Schools, Advanced Placement and Postsecondary Enrollment Options (PSEO). Research shows that dual credit is especially valuable in creating "academic momentum" leading to high school graduation and postsecondary enrollment among low-income students.

Expansion of public school choice via district options and chartered public schools also contributed. Schools such as Higher Ground Academy and Community of Peace Academy improved graduation rates for students from low-income families and for students of color. More than 70 percent of their 11th- and 12th-graders earn dual credit.

Minnesotans want continued progress. So here are several questions I hope we'll ask gubernatorial and legislative candidates:

1) How will you ensure that all youngsters from low-income families have access to strong early-childhood programs?

2) How will you encourage communities to improve services to students and families via the shared facility/community schools approach found in places such as Brooklyn Center, Northfield and Perham?

3) Since only about half of Minnesota's 11th- and 12th-graders take dual-credit courses, how will you encourage more to enroll in one or more of the technical and academic courses available?

4) How will you help educators learn from Minnesota's most effective district or chartered public schools? Whether serving a cross section or mostly "at risk" students, the Star Tribune and others have identified "Beat the Odds" schools. But they're rarely asked to help others.

5) Several of the best schools convinced graduates, including students of color, to return as educators. How will you use this and other strategies to attract and retain more and more diverse educators?

6) How will you help district and charter educators create new, potentially more effective schools? Minnesota's "teacher-powered" model has attracted district, union and charter advocates. How will you use the insights, creativity and skill of Minnesotan's finest educators?

We should be pleased but not satisfied with Minnesota's public school progress. Let's select candidates with courage and commitment for even greater growth.

Joe Nathan formerly was a Minnesota public school teacher, administrator, PTA president and education project director for the National Governors Association. He now directs the Center for School Change (