To keep or not to keep the Carnegie unit?

Study finds the credit hour useful due to lack of better alternatives

Despite its imperfections, the credit hour does not block educational innovation and still serves an important purpose, according to a study by the inventor's organization, the Carnegie Foundation for the Advancement of Teaching.

For 18 months, foundation researchers interviewed educators, policymakers, union representatives, and administrators; visiting K-12 and higher education institutions; and did archival research.

The credit hour measurement, also known a Carnegie unit, was created to standardize instruction time given to high school students. Generally, one unit equals 120 hours of instruction.

However, approximately 40 states have policies allowing students to demonstrate competency or use out-of-school work in lieu of a Carnegie unit, according to the Education Commission of the States. This has led many to call the credit hour obsolete.

'The Carnegie unit is the system'

In spite of this, the study supported the unit as a "common currency" and argued it "shouldn't be underestimated." Nixing the unit, researchers said, may make instruction quality vary even more.

"The system continues to rely on it because, in large part, the Carnegie unit is the system," says Noelle Ellerson, associate executive director for policy and advocacy at AASA, the School Superintendents Association.

In higher education, billions of federal financial aid dollars depend on the unit. In the K-12 world, staffing decisions, daily schedules, and teaching strategies are based on it. However, amid the popularity of competency-based learning, the unit fails to measure how much students actually learn.

That is because it was never meant to determine how much students know, but only that they "have the most basic resource: time to learn," says Elena Silva, study co-author.

The report also asserts the unit can be flexible enough to allow new teaching methods, while recognizing that it is not always easy.


Competency-based education does not always improve learning, according to the report. Study co-author Thomas Toch says that when examining districts nationwide, they found great as well as poor results.

ACE forms 25-school alternative credit consortium

"These innovations hold great promise, but we need to be careful not to think more innovation equals more learning," he says.

Another alternative to the unit are common-core assignments and exams, though support for the requirements varies by state.

The Carnegie unit, in short, is still valuable because no one has identified a superior replacement, though many industry experts say they believe it will eventually cease to be used.

"If the Carnegie unit was serving everyone well and everyone was coming out with a high school degree and was ready for college and careers, I don't think we'd be having this discussion. But the system's failing a lot of kids," says Carri Schneider, director of policy and research for Getting Smart, a K-12 digital learning consulting and advocacy organization (Heitin, Ed Week, 1/29).

The takeaway: A new study from the creators of the Carnegie unit finds that in lieu of a better alternative, the unit is still useful. Read more about one possible replacement, competency-based learning, here.

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