Eighteen course cancellations in the humanities this semester have some students worried about overcrowding in competitive seminars.

Several professors in the history and literature departments have gone on leave for the spring semester and canceled or moved their courses to the fall semester. While these cancellations could present administrators with convenient ways to balance the budget as Yale tries to narrow the $100 million budget gap, they also have department heads debating ways to fill gaps in the curriculum and assuage anxious students.

The decision to hire new faculty or wait for professors to return from their absences is a difficult one for administrators, Provost Peter Salovey said last week. Leaving the position unfilled can create a one-year gap in the curriculum that can increase demand for otherwise under-subscribed annual courses, Salovey said, but he added that sometimes courses can benefit from a few more students.

“Sometimes offering a course every other year can be better,” Salovey said.

Though Salovey emphasized that the Provost’s Office does not cancel courses for budgetary reasons directly, he said leaving vacancies unfilled is financially appealing because it can help to close budget deficits.

Though some canceled courses may not return any time soon, departments are restructuring offerings to ensure that students still have adequate options this spring.

Since the illness of several professors forced the cancellation of six literature courses this semester, Barry McCrea, the director of undergraduate studies for literature, has fielded “a few” panicked e-mails from students about the resultant shortage of core seminars required for the major. But McCrea said this anxiety is misplaced and reveals more about students’ academic habits than the shortcomings of individual departments.

“I deny there is a shortage of classes in the major,” McCrea said. “It is a myth that leads to an anxiety spiral.”

McCrea did change course designations to ensure adequate opportunities for majors to fulfill the core seminar requirement. Over the winter break, McCrea sent an e-mail to students in the major explaining that the department would increase the number of core seminars from four to nine. McCrea noted that any complaints about course selection could be solved if students were willing to take new and often undersubscribed courses taught by lesser-known professors instead of those taught by professors with more established reputations.

“If students weren’t all trying to take the same two courses, we would be fine,” McCrea said. “People should be curious and courageous and try new things.”

Literature major Panagiotis Progios ’12 said he chose to enroll in one of the supplementary core seminars, a class on Greek poet C.P. Cavafy. Though Progios described the subject matter of the course as “terribly specific,” student interest in the course has been strong but not overwhelming. Currently 14 students are enrolled.

Amid the frenzy of shopping period, student perceptions of overcrowding do not always match up with actual enrollment pressures. When her father fell ill, history professor Beverly Gage decided to change her “Terrorism in America, 1865-2001” from a lecture that meets twice a week to a once-a-week junior seminar to minimize disruptions to the course, creating another open junior seminar that could fill a requirement for history majors. As of Tuesday evening, 11 of the 15 permitted students were currently enrolled in the course, according to Online Course Selection course demand statistics, meaning spots are still available.

Then again, Gage’s other seminar, “Liberalism and Conservatism in U.S. Politics, 1932-1988,” is over-subscribed, with 22 shoppers for 15 seats.

Chris Moon ’11, a history major who has yet to find a junior seminar, said his shopping woes stemmed from an inability to find a course that matches his interests. Despite the high demand for junior seminars, Moon said he is confident he will be able to gain admission to his dream course when he finds it.

“Spaces are limited,” Moon wrote in an e-mail. “But I’ve found that generally professors are very accommodating and want to take on students who express interest in their seminars.”