Skipping lightly over 350 years of history, we will take the bachelor's degree as the true given of American higher education. Since we do not have a ministry of education, the definition of this degree is imprecise, variable and sometimes even fluid, as independent and autonomous institutions experiment, compete, modify, and adapt.

There are bounds, of course. States and accreditors ensure that level and scope remain consistent with commonly understood and accepted standards. Not fixed, but clearly recognizable.

Lest we be diverted, we will also have to disregard the 100 year chronology of the Carnegie Unit (CU) and focus on its present role.

In the life of a student and in the career of a teacher, four years is a very long time. The term is a more tractable unit, and at a time when colleges all offered similar programs of limited variety, it probably sufficed. Students moved through college in lock step and there was less of a need for a measure of accomplishment on a course by course basis.

That's not true anymore, and the Carnegie Unit has emerged as a means of identifying accomplishment and progress towards a degree. But it is not a mute measure of elapsed time!

Again, the fundamental given of higher education is the totality of the degree. This involves a content path, a variety of teachers, courses building on one another, and it involves strategies developed over 100 or 150 years of experience. The degree structure encourages a slow but steady change in topics and emphasis to enable courses to remain relevant, fresh, and comprehensive. This in turn enables a students to leave college and enter a job, a career, graduate program, or the professions.

The degree encompasses a generally agreed upon quantity of material delivered over four years, and the CU provides an orderly means of breaking down this totality. The degree presents a coherent track, an organized program, and a series of accomplishments, and so too must the CU.

But the Carnegie Unit is intended to be used only in conjunction with other information. Along with curriculum, catalog description, prerequisites, grades, grade point average, and distribution requirements, credit hours can help describe effort, content, and accomplishment.

A credit hour makes sense only when there is a background of distribution requirements, junior or senior level course work, a degree map, and a topic under discussion. Making progress toward a degree depends on all of these characteristics. The three credits earned in Chem I cannot be offered to replace three credits in Accounting. Indeed, poor planning could leave a student with 150 or more credits and no degree!

Everyone within higher education understands the limits of the Carnegie Unit as well as its usefulness as a medium of exchange, or a lingua franca.

The CU enables useful and easy conversations to take place between departments and among schools. Without this shorthand, every interaction would have to encompass consideration of content, rigor, and intellectual challenge. With it, a course map can be agreed upon that lists 40 courses across 10 departments in an easily comprehensible manner, without the details and minutiae of each course.

The allocation of credit hours is neither mindless nor haphazard. Credit hours are determined by the quantity of material a student is expected to acquire, by the rigor, and by the intellectual challenge he or she will face. So too, the time and effort. History, experience and professional judgment all influence the decision to assign a certain number of credit hours to a certain quantity and intensity of material.

There is within each field and each subject area a commonly understood level of prerequisites, skills, and competencies that students must bring to bear in addressing a conventional college course. A norm is established, and vigorously protected. Experts in any given field can usually look at a curriculum, a textbook, or an examination and deduce whether or not the credits being offered for the course are consistent with common usage.

There are variations of course, but within reason. A student presenting three credits in Calculus 101 will find acceptance of these credits virtually everywhere.

There is a cross-fertilization enhancing the norm that occurs as students become faculty members elsewhere, as faculty members change campuses, as students transfer, as textbooks become widely available, as graduates enter professional programs, and as accrediting team visitors travel to different campuses. Comparisons and conversations, as well as experience, all help create a common credit hour currency which speaks volumes in academe, but only haltingly everywhere else.

For the most part, it is a tenured (and largely jaundiced) faculty that jealously protects the integrity of the courses they teach and the degree that they stand for. While there may be grade inflation in some schools, there is rarely credit hour inflation.

A teacher who does not complete his/her course's goals will at one point or another hear from a colleague teaching a more advanced course to students who do not have all the necessary prerequisites. A school whose students do poorly on the bar examination will examine all aspects of the program leading to graduation. This is all part of a vast self-correcting mechanism that protects students and protects the enterprise.

Also important is the textbook marketplace, in which a handful of texts have gained widespread acceptability at least partially because there is an excellent fit with commonly agreed-upon course descriptions and the number of credits assigned.

Difficulty with allocating credit hour appears at the peripheries. Programs that are unusual in their content or structure, weekend programs, accelerated programs, study abroad, experimental and innovative programs all have a common burden: assigning a certain number of credit hours which signifies accomplishment and progress towards a degree, and which are consistent with the norms of higher education.

Courses offered in conventional format are usually associated with a certain quantity of seat time. This, in turn, provides a template against which courses delivered in unfamiliar or unconventional format can be measured. Teachers who have offered the same course on campus and online know what to expect of students at the end of a course and will also be an excellent source of information for assigning a reasonable number of credit hour to the online (or weekend, or study abroad) course.

We do not live in a wild west environment. While there are innovative and nontraditional programs of all kinds, accomplishment is almost invariably measured against existing bricks and mortar classroom time. There are glitches -- but that's all they are. With several million different courses (and assigned Carnegie Units) offered each year, a handful of extravagant claims do not a national emergency make!

In this connection it's worth noting that it is not the role of the accreditor to "give guidance" in matters relating to credit hours. The assignment of credit hours is a faculty's prerogative and responsibility. It is the accreditor's role to ensure that this was done in a reasonable manner consistent with the field and with broad norms. This, of course, is why site visitors are comprised of experts capable of making such judgments.

For completeness, it's important to mention two parties which, by design, use the credit hour as a simple measure of time.

College administration is one. Different courses require different talents, unequal effort ("I fill up two blackboards each period while he plays movies."), dissimilar exam grading burdens.... None of these factors plays a role in determining faculty salaries -- nor should they. The system works, with every faculty member teaching the same number of credit hours.

Government is the other. Student financial aid takes no notice of differences in subject area, level, course title, rigor, challenge, or school reputation. The Department of Education has avoided interfering with the internal workings of postsecondary schools and should continue to do so.

But herein lies a danger, because there is a disconnect between the Department's usage of the CU and the manner in which it is understood and used in higher education. This is the reason we are being asked to define the credit hour as a simple measure, when as noted above, its use and understandings are quite comprehensive and quite complex.

Defining the credit hour will undo the easy exchange, the ready conversations, and the fuzziness which sometime enables us to coexist. It will generate considerations of other indicators which will similarly have to be precisely defined. Will we accelerate students according to their grade point averages? Will a 4.0 student in physics trump a 4.0 in sociology (or vice versa)?

Will teachers be paid according to the number of students they teach? According to their brightness? Their preparation for the course? Will students pay more for a 45 hour program in a philosophy seminar than a survey course?

In our litigious society, we have to keep an eye on the inevitable aggrieved student. Did he fail the course because the teacher did not provide a full 50 minutes of teaching? Does humor constitute a part of the teaching hour? Does the time spent by some other student talking constitute "teaching"? How about the time spent by the teachers walking up and down the aisles watching as students work a computer assignment? And how do we determine that the student has devoted two hours of out-of-class student work? Will we have cameras, beepers, monitors? What constitutes two hours of out-of-class student work?

Defining a credit hour has implications that could conceivably cause great dislocation and misunderstanding in higher education.

If there are concerns, they are rare. And these unusual episodes should not be allowed to drive higher education, just like the rare high school "diploma mill" student should not be permitted to impose on all of higher education another costly, time consuming, and unnecessary burden.