How do the new teachers measure up?

No longer your stereotypical schoolmarm, a schoolteacher today has a profile markedly different from a generation ago. She - teachers are still overwhelmingly female - is less likely to make teaching a lifelong career. Having possibly worked in another field first, she's a bit older than her counterpart 40 years ago. Chances are, she's also more educated.

But there's one shift in the new demographic of teachers that has drawn particular attention - and concern. It seems that fewer "high-aptitude" women - those from the most selective colleges with stellar SAT scores - are becoming elementary and high school teachers.

"These teachers were never a big share, but they were a non-negligible share," says Caroline Hoxby, a professor of economics at Harvard University in Cambridge, Mass., whose research focuses on the economics of education. "People say they were important leaders. They weren't in every classroom but they were mentors." Ms. Hoxby and Andrew Leigh of the Australian National University have authored the latest study on aptitude in the newest generation of schoolteachers.

In a sense, their findings simply underscore a broader issue - the widespread need for talented teachers to step up to the chalkboard as baby boomers begin retiring. To fill the vacancies, as many as 2.2 million teachers are needed between 2000 and 2010. Certainly most experts would agree that creative new strategies must be employed to ensure the brightest are included in this bunch.

But lost in talk of how best to recruit a fresh crop of teachers has been the equally pressing problem of retention. More than 20 percent of beginning teachers quit after four years, and many barely survive the first year's baptism by fire. Some educators believe that this tough work environment and the sink-or-swim attitude toward new teachers are keeping people away.

In "Wage Distortion," however - which appears in the current issue of Education Next, a journal published by Stanford University's Hoover Institution - Hoxby and Mr. Leigh suggest that pay is the reason so few high-aptitude women opt to teach. Specifically, they cite "pay compression," whereby the salary differential between high- and low-aptitude public school teachers has narrowed since the 1960s, so that today "those with the highest aptitude earn no more than those with the lowest."

Even more troubling, say Hoxby and Leigh, pay compression has not only diminished the number of smart female teachers, but it has also increased the share of women from bottom-tier colleges who performed poorly on achievement tests. (See table, right.)

This explanation defies conventional wisdom. Most experts hold that fewer women are going into teaching than in the past because such an array of appealing career options is open to them - both service-oriented and more lucrative. Women looking to help people can become doctors or work for public-interest groups. More graduates consider law and engineering, while investment banks and management consulting firms recruit women from selective schools on campus.

As a result, the so-called "hidden subsidy of education," those talented, well-educated women - and minorities - who traditionally filled the ranks, is disappearing, says Susan Moore Johnson, director of the Project on the Next Generation of Teachers at Harvard's Graduate School of Education.

Morgaen Donaldson, a doctoral student on Professor Johnson's research team, says that during her first year teaching in a Boston public school she would be asked, "You went to Princeton. Why aren't you a lawyer?" She'd respond by asking why someone with an undergraduate degree from Princeton University shouldn't be a teacher. But Ms. Donaldson worries that some elite colleges may be sending their graduates the message that teaching is an "antiintellectual profession."

Not all research suggests that today's teachers are less able than their predecessors. According to a 2000 study by Public Agenda, the public opinion research group, about half of superintendents and principals believe the quality of new teachers has improved in recent years.

In 1999, the Educational Testing Service in Princeton, N.J., found teachers did as well as or better than other college-educated adults on three measures of literacy, including reading comprehension and math.

Of course there are other, intangible qualities effective teachers have that may not appear in studies or on tests. "How do you measure a caring teacher?" asks Jacqueline Ancess of Columbia University's Teachers College in New York.

As a group, special education teachers tend not to perform as well on standardized tests, often because they grapple with learning disabilities of their own. But it's this experience, says Barnett Berry, president of the Southeast Center for Teaching Quality in Chapel Hill, N.C., that enables them to to pass adaptive strategies on to students.

To lure talented women back to teaching, Hoxby and Leigh suggest that teachers' pay be tied to performance rather than seniority, as is often the case now.

Johnson says the Project on the Next Generation of Teachers has found that new teachers do expect differentiated pay that reflects their value and skills. It's a controversial idea that teachers unions have fought in the past. Now, all eyes are on Denver, where, with union support, the school district recently embarked on an experiment with performance pay. Still, Johnson and others warn that "performance" must be evaluated carefully, incorporating factors beyond student scores.

At the Bronx Preparatory Charter School in New York's South Bronx, performance is evaluated, among other ways, by conversations with students in addition to test scores.

Recruiting talented teachers is always a challenge, says founder and director Kristin Kearns Jordan, but she believes it's one all sectors face. Ms. Jordan graduated from Brown University in Providence, R.I. Before that she attended Phillips Exeter Academy, the preparatory school in New Hampshire - where her former history teacher told the alumni magazine, "You could see Kristin as a lawyer or investment banker. She's brought the same sort of acumen to the world of education and her vision to make a difference to children."

For a group that has proven to be inspired more by intrinsic than extrinsic motivation, pay may not be as important as economists think. Jordan says, "The people we recruit see this as a way of changing the world."

Research indicates that while most teachers do feel underpaid, unless salaries were increased substantially, other factors are more important to them. (Although Donaldson does suggest that burdensome college loans may prevent some women from the Ivy League from choosing to teach.)

In the 2000 survey, Public Agenda found that given a choice between better student behavior and parental support or a significantly higher salary, 86 percent of new teachers would choose better behavior and support; 82 percent would choose a more supportive administration over higher wages.

If Hoxby and Leigh are right, and a differentiated pay scale based on performance would draw more of the brightest women to teaching, a better working environment, with more mentoring and support, may be the key to keeping them. Teachers interviewed by the Project on the Next Generation of Teachers also said they crave more teamwork, room to grow into leadership positions, and tracks that combine teaching with other responsibilities such as curriculum development and mentoring.

Public Agenda's survey "A Sense of Calling: Who Teaches and Why" concluded that new teachers' passion for teaching is "palpable, vastly underappreciated, and a valuable asset that money can't buy."