Why Introductory Biology Loses So Many Students, and What One Instructor Can Do

By Adrian Gonzalez · Reviewed by Matthew Brewer, Ph.D., CEO of PracticeQuest

Introductory biology is a gateway course for most life-science and pre-health majors, and a large share of students do not get through it on the first try. Drop, fail, and withdraw (DFW) rates in introductory biology are commonly cited in the 20–30% range (Adkins et al., 2023). At those rates, a class of 200 loses 40 to 60 students, many of them capable students who leave biology after one bad semester.

Why are these rates so high, what has brought them down where they have fallen, and what can a single instructor do about it?

What Causes Such High DFW Rates?

Two features of course design come up again and again: how the course is taught, and how it is graded. On teaching, the strongest evidence is a meta-analysis of 225 studies, which found that students in lecture-based STEM courses were 1.5 times more likely to fail than students in courses using active learning (Freeman et al., 2014).

On grading, students themselves point to exams. A study published in 2022 surveyed 965 introductory biology students at a large public research university about whether they struggled and why (Tracy et al., 2022). Among students who struggled and blamed something about the class, exams were the second most common complaint, behind course format. Students often said they felt they knew the material but did poorly on the exams, and exam scores made up most of their grade. Many tied their struggle to study habits and to not knowing how or what to study for exams, especially in the first biology course majors take, frequently in their first semester of college. The authors' recommendations include more emphasis on low-stakes formative assessment.

That is a design problem more than a character flaw. A course graded mostly on a few high-stakes exams gives students very few chances to learn how to study before the grade is already damaged.

What Has Worked?

Beginning in the early 2010s, Oregon State University reworked its introductory Principles of Biology series (BI 21x), replacing much of the traditional lecture with active learning. Over that period, “DFW rates for the three BI 21 courses reduced from a high of 33.6% to a low of 7% during a 10-year period from 2009 to 2019” (Nayak, 2020). The changes went well beyond lecture format. A team of nearly 90 faculty, teaching assistants, and undergraduate learning assistants ran the course, students could rework parts of exams in groups, and the lab sequence was rebuilt around inquiry. The course coordinator, Lori Kayes, drew the obvious lesson: large gains in pass rates usually take many people, and they are hard to achieve with one person teaching 500 students (Nayak, 2020).

The second approach is frequent low-stakes testing. Retrieving information from memory strengthens it more than rereading does, and practice testing is one of the most consistently supported techniques in learning research (Dunlosky et al., 2013). Orr and Foster (2013) looked at this in an introductory majors biology course at Chandler-Gilbert Community College, where short online quizzes before each exam were a required part of the grade. Students who completed all of the pre-exam quizzes scored significantly higher on exams than students who completed none, and higher than the class average. The comparison is not a controlled experiment, but the benefit held for students across the range of academic ability.

What Can One Instructor Do?

Oregon State's results took a decade and a team of ninety people. Most instructors don't have that level of support, and department-wide redesigns move slowly. Changing how one course assesses students is within a single instructor's control, though it asks something real of them. Assign frequent practice for participation credit. Put the grade weight on proctored quizzes and exams. Tell students plainly that those exams draw on the same material they practiced. 

PracticeQuest’s founder, Dr. Matthew Brewer, ran this approach by hand for years while coordinating introductory biology at a large public university, where the sequence’s DFW rate fell from about 35% to about 22%, a 37% relative reduction. Doing it by hand meant writing new questions every week. PracticeQuest takes over that work.

PracticeQuest generates practice and tests from question templates written by a biology subject-matter expert, so each attempt gives a student new versions of questions aligned to the same learning objectives. Students can practice as often as they like, in short sessions spread across the term, which is the pattern the learning research favors (Dunlosky et al., 2013). Because practice earns credit for completion rather than accuracy, a wrong answer costs nothing, and there is less incentive to use AI to answer the questions. Honest practice is rewarded by better results on the proctored exam. Students can find and correct their misconceptions before the exam without jeopardizing their grade. A student who does the practice is preparing for the exam in the most direct way available, and the instructor can see who is doing it and give credit for the effort. 

If you want to see how a course like this is put together, with practice sets and a quiz drawn from the same templates, email mbrewer@practice-quest.com for preview access of a demo course.  

References

Adkins, S., Brasfield, K., Tran, T., Morris, J. J., & Raut, S. (2023). Which course resources and student approaches to learning are related to higher grades in introductory biology? Journal of Research in Science, Mathematics and Technology Education, 6(3), 175–196. https://doi.org/10.31756/jrsmte.633

Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students’ learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest, 14(1), 4–58. https://doi.org/10.1177/1529100612453266

Freeman, S., Eddy, S. L., McDonough, M., Smith, M. K., Okoroafor, N., Jordt, H., & Wenderoth, M. P. (2014). Active learning increases student performance in science, engineering, and mathematics. Proceedings of the National Academy of Sciences, 111(23), 8410–8415. https://doi.org/10.1073/pnas.1319030111

Nayak, S. (2020, January 15). Fostering student success in introductory biology. College of Science, Oregon State University. https://science.oregonstate.edu/IMPACT/2020/01/lowering-fail-rates-and-fostering-student-success-in-introductory-biology

Orr, R., & Foster, S. (2013). Increasing student success using online quizzing in introductory (majors) biology. CBE—Life Sciences Education, 12(3), 509–514. https://doi.org/10.1187/cbe.12-10-0183

Tracy, C. B., Driessen, E. P., Beatty, A. E., Lamb, T., Pruett, J. E., Botello, J. D., Brittain, C., Ford, Í. C., Josefson, C. C., Klabacka, R. L., Smith, T., Steele, A., Zhong, M., Bowling, S., Dixon, L., & Ballen, C. J. (2022). Why students struggle in undergraduate biology: Sources and solutions. CBE—Life Sciences Education, 21(3), ar48. https://doi.org/10.1187/cbe.21-09-0289