Portside

Lots of research in the past decade underscores the importance of great teachers. Summarizing these studies, the distinguished Harvard economist Raj Chetty noted that good teachers aren’t only “effective at teaching to the test and raising students’ performance on tests”; they also have a long-term impact “on outcomes we ultimately care about from education,” such as encouraging students to avoid teen pregnancy and putting them on the path to college and middle-class earnings.

During my tenure as schools chancellor in New York City from 2002 to 2011, we found that, with proper recruitment, support and incentives, we could increase the numbers of teachers who were both temperamentally and intellectually equipped for the modern classroom. We accomplished this by making our schools exciting places to work, bringing in partners to aggressively recruit talented new teachers and significantly improving our compensation system.

But if we are to raise the quality and the performance of teachers across the country, more effort must come from the profession itself. This could begin with an honest assessment of the system that educates and certifies those who become teachers. Today, despite some recent improvements, we still are not getting the best students to go into teaching.

Nor are young teachers well served by the profession as they enter it. Too often, they are hired to provide instruction in subjects outside their areas of academic expertise. This mismatch surely affects both student achievement and teacher satisfaction. Too many teachers in our big urban school systems are overworked, isolated and bureaucratically oppressed, struggling to educate students who can be exceedingly difficult to reach.

As anyone who has stood before a classroom will attest, teaching is a tough job. But if you look carefully, you can find places in the world where teachers as a group enjoy greater success, more job satisfaction and higher social standing than they do in the U.S. In China, Japan, Finland and several other countries, teachers are accorded the same level of respect as doctors.

Among Western industrial nations, Finland stands out for the consistently high scores of its students on international achievement tests. Ninety-three percent of Finns graduate from high school, and fully two-thirds of the country’s high-school graduates go on to college.

These results have attracted a great deal of attention among Americans in part because Finland wasn’t always at the top. Forty years ago, its schools ranked near the bottom in Europe. Their success today began with a commitment to reform back then, showing that sound policies can lead to much better academic outcomes.

Unlike in America, Finnish teachers are drawn from the top 10% of their college classes. They must earn a minimum of a master’s degree before applying for a job, and when they do apply, the competition is stiff. Once they are employed, Finnish teachers go through a yearlong teaching apprenticeship and, if they succeed, are required to devote two hours a week to professional development throughout their careers. Finnish teachers are permitted to try out almost any innovative method they prefer, so long as they meet certain general curriculum standards. They also collaborate freely to help students with challenges and share what they learn with one another.

The Finnish model suggests that, if we are serious about improving the quality of the people who go into teaching, we must begin by asking more of the education schools that train our teachers. Far too many of these schools function as indiscriminate revenue sources for universities and colleges, accepting underqualified students and their tuition dollars for programs that are academically weak.

To solve this problem, states could institute rigorous exams—similar to the bar exams for lawyers or licensing tests for doctors—that graduates would have to pass to be cleared for the classroom. In addition to testing pedagogy, these exams would require prospective teachers to demonstrate real subject-matter knowledge, something that is largely ignored today.

Once a bar exam for teachers becomes the norm, all sorts of services and associations would arise to support the profession and enforce standards. Like lawyers and physicians, teachers could be required to take ongoing continuing- education courses, and those who sought to specialize in certain areas such as English as a second language might be required to pass additional exams.

In time, new designations, with increased compensation, might emerge—master teacher, mentor, team leader and so on—and these too could benefit from certification tests. With such a system of rigorous certification and continuing education, the teaching profession could gain not only greater respect but also more influence over research, teacher-education programs and public policy.

Although I’d like to take credit for these ideas, they were promoted almost 30 years ago by the teachers union leader Albert Shanker. Shanker was well known because of the teachers’ strikes he led in New York City during the 1960s and ’70s (and he became even more famous when Woody Allen described him as the man who had blown up the world in the 1973 comedy “Sleeper”). Later in his career, after he left New York to head the American Federation of Teachers, Shanker became a visionary leader on education reform.

In 1985, this once dyed-in-the-wool trade unionist said, “Unless we go beyond collective bargaining to the achievement of true teacher professionalism, we will fail in our major objectives.” He called for a “second revolution in American public education”—the first being collective bargaining, which he had pioneered a quarter-century earlier.

Shanker urged teachers to embrace his agenda to protect their own economic, social and political status. But he knew this could happen only if the transformation he proposed resulted in a different, and much better prepared, teaching force.

Notably, for a union leader, he saw the parallels between the destruction of the U.S. auto industry by overzealous trade-union policies and what could happen to American public schools and their teachers. As Shanker explained in 1993, “I think that we will get—and deserve—the end of public education through some sort of privatization scheme if we don’t behave differently.” More than 20 years later, these wise words remain largely unheeded.

For the sake of students and teachers alike, we need to make teaching a well-respected profession that attracts our best college graduates. We need to pay teachers well and base their overall salary on merit and performance, not length of service. Let’s also give them the tools and curriculum support that modern technology can readily provide, helping them to be better at their craft and to use their valuable time more effectively. Most important, perhaps, let every school create a culture of accountability, where every adult strives to do better for every child every day.

These are the lessons of hope in American education, and I feel sure that we can realize them.

— Mr. Klein’s new book is “Lessons of Hope: How to Fix Our Schools,” from which this essay is adapted. He currently serves as chief executive of Amplify, the education division of News Corp, the publisher of The Wall Street Journal.