Peter Chen ’13 had shopped the perennially popular Sociology 109: “Leadership and Organizations” last fall, so he expected the course to be somewhat crowded when he visited it again Wednesday on the first day of shopping period.

But when he arrived at the start of the class, student shoppers were already overflowing out the door, blocking Chen’s entrance into the lecture hall.

“I tried to push in a little bit and funnel into the room,” said Chen, who was forced to stand outside the lecture hall for about 10 minutes before wiggling his way into a newly empty chair.

Another Sociology 109 shopper, Stephanie L. Grayson ’14, said she showed up a full 20 minutes early to ensure a seat in the class, which she suspected would be crowded because it was taught by popular sociology lecturer David L. Ager. The course—which will be lotteried down to 80 students by the end of shopping period—drew about 180 shoppers, according to Ager.

This year, as the College moves to better anticipate student enrollment before the semester begins, undergraduates continued their sometimes unpredictable practice of shopping for classes.

This is the second semester since the implementation of the Pre-Term Planning Tool—which requires students to indicate the classes they plan to take in the upcoming term.

While College administrators say the tool predicts final enrollment numbers and not shopping patterns, many professors said that the tool also helped them to estimate how many students would show up during shopping period.

But those estimates are never perfect.

Arleen Aguasvivas ’15 had to sit on the floor at the crowded first lecture of Ethical Reasoning 30: “The Just World,” a new General Education course that she said she did not expect to be so popular.  She estimated that the course drew about 100 shoppers.

On the other hand, Christopher F. Allison ’12 was not surprised when he was forced to sit in the aisle in the packed first lecture of English 157: “The Classic Phase of the Novel,” which drew about 150 shoppers in its second year after being modified to fulfill the Aesthetic and Interpretive Understanding Gen Ed requirement.

“Any sort of class that counts for a Gen Ed and is rated above a ‘4’ in the Q Guide is going to be really, really crowded,” Allison said.

Another Gen Ed course—Culture and Belief 22: “Concepts of the Hero in Classical Greek Civilization”­—drew about 100 students, a turnout that was “a bit larger” than the number predicted by Pre-Term Planning, according to Professor of Classical Greek Literature Gregory Nagy.

Notably absent among Wednesday’s big classes was the perennially well-attended Government 1540: “The American Presidency,” which is not being offered this fall for the first time since it was introduced in 1993. The class’s professor, Roger B. Porter, is on sabbatical.

—Staff writer Rebecca D. Robbins can be reached at rrobbins@college.harvard.edu.