Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Chemistry

Major Professor

Scott E. Lewis, Ph.D.

Committee Member

Jeffrey R. Raker, Ph.D.

Committee Member

James W. Leahy, Ph.D.

Committee Member

Leia K. Cain, Ph.D.

Keywords

assessments, program evaluation, science education reform

Abstract

Reducing the inequities propagating the lack of representation in Science, Technology, Engineering, and Mathematics (STEM) careers has become a national imperative made increasingly complex given the inequitable preparations in science and mathematics students experience before college. A common institutional-level approach to promoting equity is the use of math and science prerequisites to prepare students who seek to enroll in lower-level STEM coursework. However, the literature does not support the efficacy of this approach, finding no substantive improvement to student performance despite considerable financial and time costs to students, instructors, and universities alike. Set in first-semester General Chemistry courses taken early in STEM degree programs, these works sought to identify and address the systems in place that contribute to inequitable STEM education and provide a cost-effective and research-based alternative to the prerequisite approach.

Students were identified as at-risk by having scored in the bottom-quartile of math composite SAT or ACT scores (or 25% of the overall cohort). Often representative of students scoring near or below national averages on the SAT and ACT, at-risk students achieved 43.8% of failing grades (D, F, W) in chemistry courses and comprised only 9.9% of the A’s awarded. Of these students at-risk, a disproportionate number self-identify as Black/African American or Hispanic/Latino suggesting that preparation in secondary-school mathematics, using SAT and ACT as a proxy, is not equitably achieved (or measured) by students of underrepresented minorities in the sciences.

First, the impact of a collaborative pedagogy (peer-lead team learning) on student performance and equity was examined. Instructor-level differences were observed wherein student performance improved in 3 of the 4 instructors’ classrooms when enacting peer-led team learning. Significant reductions in the equities observed between at-risk chemistry students and not-at-risk chemistry students were observed in classrooms of 2 of the 4 instructors.

Then, student responses to 32 assessments spanning eight semesters were analyzed in first-semester General Chemistry classes at a large, doctorate-granting institution in the Southeastern United States. Students’ performance on assessment items coded by topic presented a consistent pattern of differential performance on items designed to measure proficiencies with the mole concept and stoichiometry, a topic fundamental to student success in General Chemistry I and II in addition to Analytical Chemistry.

In an analysis of students’ solution processes to assessment items of these topics, differential performance could not be attributed to differences in conceptual understanding nor mathematical prowess, but rather the frequency in which students with higher math composite scores arrived at a correct answer using a chemically flawed or inaccurate solution process. Based on these results, we concluded that assessments of these topics may reward rote memorization without the conceptualization of procedural approaches to chemistry while simultaneously exacerbating the inequity observed between students of differing preparations in mathematics.

Finally, to evaluate our recommendation of assessments that measure students’ understanding of the topic beyond the application of procedural knowledge, heuristics, and algorithms, items were designed to encourage students’ attention to and organization of their solution processes. Student performance (overall) improved by an average of 8.5% while reducing the differential performance observed of students at-risk by as much as 12.4% (more than one letter grade).

These works contribute a variety of perspectives to science education, not the least of which is the importance of understanding the source of inequity before enacting intervention for a group of students to prevent unintended negative consequences. Implications include practical examples of assessment items reoriented from promoting a series of decontextualized algorithmic procedures toward those promoting the conceptualization of foundational science concepts. Future works seek to investigate the impact of these changes in assessment on student performance, retention, and equity when modeled in instruction and assessed throughout the semester.

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