Let's start with full disclosure: I have known Joel Klein for nearly 30 years and consider him to be one of the smartest, most grounded, most public-spirited people I have ever known — right up there with the other two old friends I would include in that characterization, Bill and Hillary Clinton.

In 2002, New York City Mayor Michael R. Bloomberg exhibited his well-known impressive powers of persuasion and political boldness by convincing Mr. Klein, a former Clinton White House deputy counsel and assistant attorney general for antitrust, to leave a seven-figure job as chief executive of an international corporation and become chancellor of the New York City public school system, which pays less than one-tenth of that.

I hadn't seen Mr. Klein for several years and just recently caught him at a Rotary Club lunch in downtown Manhattan. He was born in the Bronx, raised in a Queens public housing project and attended public schools. When he approached the daunting job of trying to improve the New York City public school system, it came down to one concept and three basic principles.

The concept: Put children first.

The three principles he relied on: public school leadership, incentives for teacher quality and accountability. His approach has produced some demonstrable progress. For example:

• Between 2002, the year of Mr. Klein's arrival, and 2008, there has been a steady growth in the city schools' four-year graduation rate, increasing by 11 percentage points.

• Compare New York City's results to those of the state's other "big four" cities — Buffalo, Rochester, Syracuse and Yonkers — which have comparable shares of low-income minorities in their populations. In 2002, New York City's fourth-grade math results were 27 percent lower than the average for the rest of New York state, with the "big four" suffering the about same gap, 31 percent behind. In 2008, after six years under Mr. Klein's leadership, New York City was now just 8 percent behind the rest of the state, whereas the other "big four" were 25 percent behind.

• In 2002, the math gap between New York City eighth-graders and those in the rest of the state was 30 percent. By 2008, it had dropped to 18 percent. Meanwhile, the big four had a 40 percent gap in math results in both 2002 and 2008.

There was also a modest closing of the gap in English and language arts between New York City and the rest of the state, when compared to the performance of the state's other major urban areas.

(To state the obvious, the data comparing New York City to the rest of the state is somewhat inapt, with the rest of the state being more affluent, whiter and with far fewer non-English speaking immigrants — all of which, self-evidently, will tend to produce higher English and math scores on standard tests than the economic and ethnic mix of New York City.)

Mr. Klein's principles are being borne out. In his first three years as chancellor, he raised more than $70 million in private philanthropic money to finance world-class leadership training courses for public-school principals and other administrative leaders. The result was an impressive group of dedicated principals and leaders, who were inspirations and motivators for both students and faculty.

The second principle was to focus on creating incentives for teacher quality. Mr. Klein favors higher pay in general for public school teachers and has introduced bonuses and higher pay for principals and teachers willing to teach in lower-income school neighborhoods and for those whose performance in a particular school merits such increases.

And that leads me to the third Klein principle — accountability. There may be many ways to screen out inferior principals and teachers and to hold them accountable. But as of now, one important way seems to be uniform tests of students so that their performance can be compared to other students of the same age and grade in the same community, city, state and even nation.

The repeated knock on uniform testing — which made President Bush's and Sen. Edward Kennedy's (D-Mass.) No Child Left Behind program a favorite punching bag of some liberals and teachers unions — is that it focuses too much on "teaching to the test," i.e., on preparing the children for getting good scores on the tests rather than teaching a broad curriculum in the classroom.

There is some validity to that concern. But in the final analysis, I never understood this argument as a reason for not using any standard tests as one means of measuring performance. I'd rather have teachers focusing on "teaching to the test" versus having little or no objective way to measure a child's progress as compared to others.

Are tests perfect? Of course not. Can they be misused? Of course. Jim Collins, in his book, Good to Great and the Social Sectors (2005), put it best:

To throw up our hands and say, “But we cannot measure performance in social sectors the way we do in business” is simply lack of discipline. All indicators are flawed — whether qualitative or quantitative. Test scores are flawed, mammograms are flawed, crime data are flawed, customer service data are flawed, patient-outcome data are flawed. What matters is not finding the perfect indicator, but settling upon a consistent and intelligent method of assessing your output results, and then tracking your trajectory with rigor.

Or as Al Shanker, the late president of the New York City United Federation of Teachers in the 1960s, stated: "The key is that unless there is accountability, we will never get the right system. As long as there are no consequences if kids or adults don't perform, as long as the discussion is not about education and student outcomes, then we're playing a game as to who has the power."

So to my old friend Mr. Klein I say: You are right. Keep your eye on the theme of your leadership as chancellor — "Children First" — and on the three principles that will make a difference in public school education not only in New York City but across the nation: individual public school leadership, teacher quality and accountability.

President Obama's new secretary of Education recognized the significance of what Mr. Klein is doing in New York City. It's no accident that one of his first visits as Education secretary was to visit with Mr. Klein last November 2008 and study his methodology — calling him "someone I've learned a tremendous amount from."

Wouldn't it be good for our children and great for our country if public school principals, teachers and their unions, politicians and parents across the country could embrace Mr. Klein's three principles — and join with him in putting children first in their local public school systems?

This piece appeared in The Washington Times on Monday, March 9.