Lori Sturdevant's column ("K-12 as we know it is on the move," Jan. 18) did an excellent job summarizing many of the reasons that I have worked for more than two decades to increase the number and the diversity of high school students who take college-level classes. But while encouraging more high school students — especially students of color and low-income students — to take dual-credit courses is unquestionably a good idea, it does not address the most urgent and complex educational challenge facing our schools and our state today.

In 2014, almost 11,000 Minnesota high school students scored at the lowest level on our state's 10th-grade reading test. This amounted to 18.3 percent of all of the students who took the exam. On the 11th-grade math test, 15,900 students scored at the lowest level, which amounted to 27.3 percent of all students tested.

According to the Minnesota Department of Education, students who score at those low levels "succeed at few of the most fundamental skills" in reading and mathematics. Many of those students are, in fact, semiliterate and seminumerate.

These are the teenagers you meet in a convenience store who can't calculate the correct change when the register doesn't tell them the exact amount. These are the older adolescents in your workplace or your community who write you a note so filled with grammatical errors and misspellings that it is difficult to discern exactly what they are trying to say.

When I ask educators and policymakers across Minnesota and the nation about their strategies for helping those low-performing students succeed, they often tell me about their efforts to prepare more students of color and low-income students for success in higher education. Those are important efforts, but the problem with that response alone is this: taking college-level courses will not address the deep gaps in academic knowledge and skills that limit the life chances of students who are two, three or more grade levels behind in reading, math and other subjects.

That is why we must broaden our strategy for closing achievement gaps at the high school level, beyond expanding participation in dual-credit courses. In my view, a more comprehensive and effective approach should include at least three essential elements.

First, we should identify the educators, schools and programs that are successfully teaching reading, math and other subjects to older students who are far behind, and then we should share and further strengthen their approaches through networked improvement communities across the state.

Second, we should help struggling high school students build caring relationships with adults inside and outside of school who can provide them with the support and challenge they need to work hard and overcome obstacles.

Third, we should reinstate a reasonable graduation test that requires young people to demonstrate that they have mastered the basic skills needed for success in today's economy.

Because the idea of an exit exam is complex and controversial, let me add that I only support taking that step if the other two elements of the strategy I suggest are implemented as well. Without increased support for teachers and more caring relationships for students, a graduation test won't do much good and could do significant harm. But with those elements in place, I believe that an exit exam would push and help schools to intervene with students who would otherwise enter adulthood without the knowledge and skills they need to earn a living wage.

None of these proposals for helping struggling high school students should replace or undermine initiatives that are already underway to help more students in the academic middle enter and succeed in higher education. But we must acknowledge that those efforts to move the middle will not benefit the young people at the bottom of the distribution of achievement in our schools.

A rising educational tide does not lift all boats. It is time to develop a serious strategy for the struggling older students who need it the most.

Kent Pekel is president and CEO of the Search Institute.