MEASURING CONTENT-KNOWLEDGE GAINS IN A LECTURE-BASED ENVIRONMENTAL SCIENCE CLASS

Students in most sections of an introductory environmental-science lecture showed significant and substantial increases in content knowledge, even though most of the class time was spent on lecture. The learning gains were similar in both online and face-to-face sections. The class, Sustainable Earth, addresses a wide variety of topics, including evolution, ecology, pollution, environmental legislation, agriculture, and energy. It has no pre-requisites and attracts students from a wide variety of majors. The lecture is accompanied by a discussion-based lab, for which the students read a pair of articles on topics related to the lectures and discuss them. Student understanding of the lab topics was not assessed in this study.

Students take a pre-test on the first day of class and answer the same questions on post-test on the final day of class, 14 weeks later. The test consisted of 11 multiple-choice questions about topics in the textbook, not those addressed in the lab. It had originally been developed for accreditation purposes, since this class is used to fulfill a science requirement at a state-funded university. Since neither test involves a large grade, many students missed one or the other; only 115 of the 209 students ended up taking both tests. The average normalized gain on the paired tests was 24%, equivalent to a Cohen’s D of 1.34 standard deviations (p < 0.0001 on a paired t-test).

Between Fall 2020 and Spring 2023, two of the five sections of the class were taught entirely online and three were taught face-to-face. All students used the same textbook, though one section used a new edition with one new module which was not included on the pre-/post-test. Student grades in both the online and face-to-face sections were mostly determined by open-book online multiple-choice quizzes that they were allowed to retake and by timed tests that they were allowed to take as either individuals or as part of a collaborative team. The lecturer would pause and have the students answer a question related to the lecture at least two or three times a class. The online and face-to-face sections of the class were taught and assessed similarly, which may explain the similarity in test scores and gains measured in both types of sections. Even a slight admixture of active learning seems to improve student learning.