Despite competition from an alternative economics course, Social Analysis 10, “Principles of Economics” (Ec 10), has remained one of this year’s most popular classes.

But only 629 students enrolled in the course this fall, compared to 717 last year, according to preliminary course enrollment numbers released by the Office of the Registrar yesterday.

Social Analysis 72, “Economics: A Critical Approach,” a semester-long alternative to the introductory economics course, is being offered for the first time this year.

Eighty-five students have signed up to take that course, taught by Barker Professor of Economics Stephen A. Marglin ’59.

But Marglin said he was unsure whether his class is responsible for the decline in enrollment in Ec 10, which is taught by Baker Professor of Economics Martin S. Feldstein ’61.

“It’s a reasonable hypothesis,” Marglin said, noting that there are relatively few first-years enrolled in his course, whereas Ec 10 generally attracts hundreds of first-year students.

Feldstein said the new alternative course—which doesn’t satisfy requirements for economics concentrators—might draw other students away from his year-long Ec 10 course because it was only one semester long, but also said that higher Advanced Placement exam scores might account for the drop.

“I assume that some of our decline in enrollment is due to the desire of some students to get some economics in a single term,” he wrote in an e-mail. “There may also be an increasing number of students who have “five” scores on the micro and macro AP courses which provides a basis for going on to higher level courses even if they want to concentrate in economics.”

Though Ec 10 has been Harvard’s most popular course for the last three years, Moral Reasoning 22, “Justice”—which ranked second last fall—took the lead this year with an enrollment of 901.

With 686 students in 2002, the class saw a dramatic increase in enrollment.

“I think a lot of people took Justice this year because they knew the class isn’t being offered next year,” said Stephen E. Dewey ’07.

“The fact that so many students take the course means that class debates can continue over lunch and dinner, in the

Houses and in the Yard,” Harvard College Professor and Professor of Government Michael J. Sandel wrote in an e-mail. “The real learning takes place when the Justice class spills out of Sanders Theater and into students’ lives.”

In 1987, a record 948 students enrolled in the class.

Despite the large size of the class, many students said they do not feel overwhelmed by the course.

“[Professor Sandel] makes an effort to make the class feel smaller than it is by having people state their names when they talk,” said Jessica R. Rosenfeld ’07.

Though the enrollment numbers aren’t nearly as large as Harvard’s biggest courses, more students have signed up to take Arabic this year.

“Last year and this year there have been precipitous leaps in the number of students in first year Arabic. Almost 90 students have enrolled,” said Director of the Arabic Language Program William E. Granara. “There are students from the Law School, the Divinity School and the Kennedy School of Government, but there are also more freshmen studying Arabic because of the issues in the Middle East which have received great national attention.”

One such first-year is Raymond L. Palmer ’07, who said his initial desire to study the language was the result of his interest in Middle Eastern culture.

“I went to a Model United Nations Conference and met many friends from Iraq, Jordan and Lebanon [and others from the Middle East],” he said. “They spoke Arabic and I got fascinated by the language.”

Core Curriculum classes continue to see some of Harvard’s largest undergraduate enrollments. Other popular courses this year include Literature and Arts C-61, “The Rome of Augustus,” Literature and Arts B-82, “Sayin’ Something: Jazz as Sound, Sensibility, and Social Dialogue” and English 13, “The English Bible,” which satisfies the Literature and Arts A requirement.