Choosing online or in-person biology laboratories: student motivations, perceived costs, and comparable learning outcomes.

Online laboratory instruction has increased in undergraduate STEM education in response to higher demand for flexible learning environments, yet motivations underlying students' modality choice often remain little understood. Grounded in expectancy-value theory (EVT), we examined why students selected online asynchronous or in-person sections of an introductory biology laboratory course (N = 135), using a mixed-methods design that integrated qualitative data, institutional records, and performance metrics. Students reported distinct reasons for modality choice: online students mainly cited flexibility, logistics, and workload considerations-cost-related themes-while in-person students often cited learning style and social preferences-value-related themes. Online students had completed more total credits and were more likely to identify as female than in-person students. Age, GPA, race/ethnicity, first-generation status, transfer status, non-traditional student status, and course-requirement status did not differ between groups. Notably, the reported cost-related themes were not mirrored by significant differences in measured structural constraints, such as work hours, caretaking responsibilities, or commuting distance, suggesting perceived rather than objective cost as the driver of modality choice. Online students reported significantly lower laboratory confidence than in-person students, consistent with a difference in expectancy of success. Despite these motivational and confidence differences, student performance did not differ significantly between modalities across all measured performance outcomes. Overall GPA was the strongest predictor of academic success. Our findings support expectancy-value theory as a useful framework for understanding modality choice in undergraduate laboratory courses and indicate that well-designed online laboratory courses can broaden access to undergraduate STEM education without compromising learning outcomes.