Search for: All records

Abstract 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. 

Conceptually understanding chemistry requires the ability to transition among representational levels to use an understanding of submicroscopic entities and properties to explain macroscopic phenomena. Past literature describes student struggles with these transitions but provides limited information about upper-level post-secondary chemistry students’ abilities to transition among levels. This group is of particular interest as they are engaging in potentially their final training before entering a career as professional chemists, thus if students are likely to develop this skill during their formal education it should be manifest among this group. This study characterized analytical chemistry students’ responses to open-ended assessments on acid–base titrations and thin-layer chromatography for the use of sub-microscopic entities or properties to explain these macroscopic phenomena. Further, to understand whether explanatory statements were an expectation inherent in the instructional context of the setting, the analytical chemistry instructor's lectures on acid–base titrations and thin-layer chromatography were analyzed with the same framework. The analysis found that students seldom invoked explanatory statements within their responses and that congruence between lectures and responses to assessment was primarily limited to the use of macroscopic, descriptive terms. Despite the fact that the lecture in class regularly invoked explanatory statements in one context, this did not translate to student use of explanatory statements. To further test the hypothesis that analytical chemistry students struggle with explanatory statements, a follow-on study was also conducted among a second cohort of students reviewing their responses when specifically prompted to use sub-microscopic entities to explain a macroscopic phenomenon. The results suggest that fewer than half of the students showed proficiency on generating explanatory statements when explicitly prompted to do so. Instructional implications to promote explanatory statements are proposed in the discussion. 

Students who score within the bottom quartile on cognitive measures of math aptitude have been identified as at-risk for low performance in chemistry courses, with less attention as to why such differential performance persists. At-risk students struggle most differentially on assessment items related to the mole concept and stoichiometry. An exploration as to the nature of the differential performance observed became of great interest as the assessment of these topics rarely progresses beyond multiplication or division, and at-risk students who achieved proficiency with the mole concept and stoichiometry had no noticeable gaps in academic chemistry performance when compared to students scoring in the top three quartiles of math aptitude. Thus, students in first-semester general chemistry were surveyed to describe their solution processes toward assessment items involving the mole concept and stoichiometry. Three hundred and forty-eight students responded to all survey prompts with 101 identified as at-risk. Findings suggest that while all students were observed to struggle in the conceptualization of the algorithms by which they execute solution processes, not-at-risk chemistry students were more likely to achieve correct answers via chemically implausible solution pathways. Rather than suggest the removal of assessment practices involving algorithmic, multiple-choice assessment on these topics, the implications include practical suggestions and opportunities for further research toward improving the equitability of measures used to assess proficiency with stoichiometry.