Given the centrality of argumentation in the Next Generation Science Standards, there is an urgent need for an empirically validated learning progression of this core practice and the development of high-quality assessment items. Here, we introduce a hypothesized three-tiered learning progression for scientific argumentation. The learning progression accounts for the intrinsic cognitive load associated with orchestrating arguments of increasingly complex structure. Our proposed learning progression for argumentation in science also makes an important distinction between construction and critique. We present validity evidence for this learning progression based on item response theory, and discuss the development of items used to test this learning progression. By analyzing data from cognitive think-aloud interviews of students, written responses on pilot test administrations, and large-scale test administrations using a Rasch analysis, we discuss the refinement both of our items and our learning progression to improve construct validity and scoring reliability. Limitations to this research as well as implications for future work on assessment of scientific argumentation are discussed. #

Successful completion of organic chemistry is a prerequisite for many graduate and professional programs in science, technology, engineering, and mathematics, yet the failure rate for this sequence of courses is notoriously high. To date, few studies have examined why some students succeed while others have difficulty in organic chemistry. This study examines factors related to student performance in organic chemistry courses. Results indicate that high-achieving students, as measured by course grades, score higher on measures of conceptual performance and problem-solving while seeking assistance and engaging in practice problems earlier in the semester than low-achieving students. Case studies illustrate how students engaging in such behaviors can overcome poor prior grades while those not engaging in such behaviors can perform poorly despite strong prior grades. Overall, study behaviors and conceptual understanding outweigh prior academic standing in predicting final course grades. These analyses suggest potential intervention targets for educators addressing students at risk for poor organic chemistry performance.

This study sought to identify ethnically diverse students'study strategies in organic chemistry and their relationships to course outcomes. Study diaries, concept maps, and problem sets were used to assess study outcomes. Findings show that students engage in four commonly used reviewing-type strategies, regardless of ethnic group affiliation. However, these common strategies were rarely associated with students' problem solving, concept mapping, or course performance. In addition, students seldom engaged in metacognitive and peer learning strategies despite their reported benefits in the literature. Implications for research and practice are discussed in light of these findings. # 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 660-676, 2013

Chemistry courses remain a challenge for many undergraduate students. In particular, firstsemester organic chemistry has been labeled as a gatekeeper with high attrition rates, especially among students of color. Our study examines a key factor related to conceptual understanding in science and predictive of course outcomes-knowledge structures. Previous research on knowledge structures has focused on differences between experts and novices. Given the increasing ethnic diversity of college classrooms and research indicating unique differences in certain higher order cognitive processes associated cultural practices and ethnicity, it is important to investigate whether similar patterns exist with respect to knowledge structures. Our study utilized concept maps to measure knowledge structures. Two separate analyses where performed to determine whether or not ethnically diverse students' organize their knowledge of organic chemistry content in structurally different ways. The first analysis utilized concept map proposition scoring to examine the influence of prior science achievement and ethnicity on knowledge structures. The second analysis examined holistic map structures to determine whether or not ethnically diverse students show qualitatively distinct structures overall. Results show significant mean differences on concept map proposition scores related to both prior science achievement and ethnic group membership. However, examination of holistic structures revealed that students' qualitative holistic structures did not vary by ethnic group membership. Taken together, our findings suggest that variation in students' knowledge structures are related to prior science achievement across ethnic groups, not qualitative differences in the ways ethnically diverse students' structure knowledge. Implications for teaching and learning in organic chemistry are discussed. #

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