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This study describes an evaluation of the Peer-Led Team Learning (PLTL) reform model in first-semester general chemistry. PLTL was implemented in place of one-third of the available lecture time, maintaining the same amount of structured class time under the reform. The evaluation demonstrates that classes implementing the PLTL reform at the setting featured a statistically significant improvement of 15% in the pass rate for the classes, compared to conventional, lecture-only classes at the same setting. Additionally, the PLTL classes maintained a comparable score on a comprehensive American Chemical Society final exam to that of the conventional classes. Combined, these findings suggest that the improvement in pass rates occurs while maintaining the same level of rigor in the PLTL classes. Examining student groups shows that students in underrepresented minority groups demonstrated the largest improvement in pass rates with the PLTL reform.

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This study employed hierarchical linear models (HLM) to investigate Peer-Led Guided Inquiry (PLGI), a teaching practice combining cooperative learning and inquiry and tailored for a large class. Ultimately, the study provided an example of the effective introduction of a reform pedagogical approach in a large class setting. In the narrative, the strengths of HLM as a statistical technique are discussed in the context of pedagogical reforms, and the case is made for the use of HLM in rigorous determinations of both effectiveness and equity associated with reform practices. The implementation of PLGI in a college-level general chemistry course is also described. For the study, two general HLM models suited to investigating reform were developed and utilized to examine the effectiveness and equity of PLGI as implemented in this setting. The models showed that the reform was associated with statistically significant improvement over traditional pedagogy in terms of academic performance on multiple measures, but achieving equity remained elusive: the consequences of pre-existing achievement gaps did not lessen as a result of reform implementation. The analysis led to several implications for educational research, particularly in terms of evaluating pedagogical reforms, as well as for teaching. Choosing effective and equitable pedagogies for classroom implementation remains a critical goal for classes of any size. ß

General chemistry is a required first step for students who wish to pursue a career in science or health professions. The course often has low rates of student success and as a result serves as a gateway limiting access to science fields. This study seeks to better understand factors that are related to student success in general chemistry by focusing on the affective domain, in this case students' self-concept, or self-evaluation of ability as it pertains to a specific field of study. First, a profile of students' self-concept in the general chemistry setting is created. Next, the relationship between self-concept and success in the course is investigated, including examining the role of self-concept after taking into account a cognitive measure (SAT scores). This study is unique in that evidence is found for the impact of self-concept after taking into account a cognitive measure. Finally, the effect of a semester-long, inquiry-oriented learning environment on students' self-concept is described. Suggested interventions to improve student self-concept are also discussed.

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The identification of students at risk for academic failure in undergraduate chemistry courses has been heavily addressed in the literature. Arguably one of the strongest and most well-supported predictors of undergraduate success in chemistry is the mathematics portion of the SAT (SAT-M), a college-entrance, standardized test administered by the College Board. While students scoring in the bottom quartile of the SAT-M (herein referred to as at-risk) perform significantly worse on first-semester chemistry assessments, little is known of the topics on which these students differentially struggle. The purpose of this study is to provide insight as to which first-semester chemistry topics present an incommensurate challenge to at-risk students. Students were identified as either at-risk or not at-riskviaSAT-M scores. Students’ assessment responses were collected across four semesters of first-semester chemistry courses at a large, public university (N= 5636). At-risk students struggled consistently across all topics but disproportionately with mole concept and stoichiometry. Analyzing the trend in topics suggests that the struggles of at-risk students are not entirely attributable to topics that rely heavily on algorithms or algebraic math. Moreso, at-risk students found to have performed well on mole concept and stoichiometry went on to perform similarly as their not at-risk peers. The results support an instructional emphasis on these topics with reviewed literature offering promising, practical options to better serve at-risk students and broaden representation in the sciences.

Investigating the effectiveness of instructional practices provides an evidence base to inform instructional decisions. Synthesizing research studies on instructional effectiveness provides an estimate of the generalizability of effectiveness across settings, along with an exploration of factors that may moderate the impact, which cannot be achieved within individual studies. This study sought to provide a synthesis of evidence‐based instructional practices (EBIPs) particular to chemistry through meta‐analysis. Ninety‐nine studies were analyzed comprising a broader view of chemistry specific studies than past meta‐analyses. The results showed that EBIPs feature a demonstrably positive impact on students' academic performance in chemistry, although assessment topic coverage and setting size emerged as relevant moderators of impact and prevented making definitive conclusions of the relative impact of each EBIP. In examining publication bias, an asymmetric distribution of studies based on standard error (SE) and effect size was found, indicative of potential publication bias. To explore the potential impact of bias, the trim and fill method was employed resulting in a range for the overall weighted effect size from 0.29 to 0.62. The study concludes that evidence‐based instructional practices have demonstrated effectiveness even in consideration of potential publication bias, as the range of effect sizes remains positive, but highlights the continued need to publish null findings in the research literature.