Would you expect a cardiologist to do the work of a gastroenterologist? No. So why do we expect a strong reading teacher to also be equally as talented in math? The fact that we expect the latter and not the former gets to the heart of one of the biggest challenges we face in improving the teaching profession and American public education as a whole.

When it comes to teachers, school reformers and education traditionalists talk plenty about overhauling how teachers are recruited, changing the way they are trained, revamping the array of costly, ineffective degree- and seniority-based compensation packages, and subjecting them to more-rigorous success-based performance management. All of these discussions are critical. But one of the most-important conversations is the one that is also the one least-considered: Re-imagining the very ways teachers work in classrooms and how principals oversee what they do.

As Stanford University Professor Linda Darling-Hammond has astutely noted, teacher training is in the same state that medical training was a century ago, before the work of Abraham Flexner and the Carnegie Corp., led to improvements in how doctors are selected into med schools and taught how to conduct exams and surgeries. The same is true for the actual work of teaching. As doctors were expected back in the 19th and early 20th centuries to be jacks of all trades instead of being allowed to become dedicated specialists working efficiently in hospitals and practices, teachers are expected to be general practitioners when it makes more sense for them (and for schools) to become master specialists in aspects of student learning.

In elementary schools, teachers are generalists expected to provide high-quality reading, math and science instruction to students, regardless of their own aptitude in those subjects. This, in spite of the growing evidence that this isn’t even close to possible. As the Los Angeles Times revealed last year in its value-added analysis of elementary teachers working in the L.A. Unified School District, some teachers have strong competency in reading while lagging behind in math teaching, while others are stronger in math teaching than in reading and writing. At Shirley Avenue Elementary in suburban Reseda, for example, only a couple of the teachers analyzed by the Times, Paul Wainess and Mark G. Gendernalik, were strong in both reading and mathematics; the rest were either strong in one of the two subjects, or in many cases, barely treading water in either one.

Even within a particular subject, some teachers are going to have real expertise in one aspect than another. Some teachers, for example, are really going to be skilled in providing intensive reading remediation to struggling readers. Others may have strong expertise in addressing aspects of writing and composition, which is also important for students in their future success. And still others may be good in dealing with areas such as phonics. One can even go further, with teachers becoming reading and math specialists for students in particular grades; after all, kindergartners who need to learn quantities don’t have the same needs as fifth graders who must be able to understand that equal signs are the first steps in understanding the algebraic equations they must master three grades onward.

This specialization extends even into middle schools and high schools, where kids begin going from class to class to teachers who are already specialists of a sort. But given that our kids who have had abysmal instruction in the early grades may need help in other areas, there is a need for even more specialization. For students who struggle with memorizing geometry, they may need a math teacher who has also become a specialist in helping kids acquire and retain knowledge; that teacher can also help those students learn new memorization skills they can apply to other classroom activities. Other teachers can become masters as helping kids left back a grade quickly get up to speed on the subjects they must master and assist them in dealing with the psychological issues that can sometimes come with being held back.

Breaking up teaching into specialties could do wonders for students, providing more-specialized instruction that will address their needs. As Arthur McKee of the National Council of Teacher Quality points out, it can also help schools. After all, specialization has helped the medical profession improve patient care, develop innovative treatments, and improve quality of life for society as a whole by allowing doctors in different fields to address our wide array of ailments and needs. For schools and districts, specialization can allow principals and superintendents to divide up work efficiently, thoughtfully, allowing for the most-meaningful forms of customizing instruction to the needs of children in classrooms.For example, a district can put together a group of teachers with success in improving the achievement of English as Second Language students, and have them go from school to school addressing particular issues. Or a principal can do something similar within his own school.

It can even improve the teaching profession itself. The lack of meaningful career paths and opportunities to grow as professionals is as much a reason why teaching remains unattractive to talented collegians as the seniority-based privileges that fail to reward good and great teachers for their success in improving student performance. Specialization can allow teachers to build expertise in particular subjects and sub-areas within them, gain recognition (and even financial reward) for their work as masters in those particular learning areas. It can also nurture the entrepreneurial talents that teachers must have to be able to do the work of improving student achievement no matter the challenge.

Given that the high-quality teachers we want in our classrooms are likely to also be the kinds of talents who will eventually be bored with just working in one classroom, expanding the range of opportunities for them to stretch and do great work is critical to improving the talent pipeline into American public education. It can also spur the very collaboration that so many teachers and education players consider to be a key to improving student achievement. Teachers could follow the path of doctors and start their own instructional practices that serve particular learning needs.

The tools for allowing this specialization are already here. Thanks to Value-Added Analysis of student performance data, we can pinpoint the areas in which elementary school teachers (and even those at the secondary level) are strongest; the development of formative assessments also allows for the analysis of teacher strengths. While the science of reading and mathematics is still developing, there are plenty of areas in which teachers can be come master instructors. All that is needed is for that data to be used, for strong, performance-based assessments than can help teachers hone their strengths, and for ed schools and alternative teacher training programs to improve their offerings (as well as become more-selective in their recruiting). Given that medical schools and the entire healthcare sector has paved the way for specialization, ed schools and the rest of American public education can build upon that work and take it further.

At this moment, however, instructional specialization doesn’t come up in the thinking of ed school professors, policy wonks, NEA and AFT presidents, or elementary school principals. This is a shame. The challenges of overhauling American public education require abandoning a 19th century model of how teachers work that doesn’t serve children, families, taxpayers or even teachers themselves. It is high time that specialization becomes a part of education.