Language of mechanisms: exam analysis reveals students' strengths, strategies, and errors when using the electron-pushing formalism (curved arrows) in new reactions
Why this work is in the frame
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Bibliographic record
Abstract
This study investigated students' successes, strategies, and common errors in their answers to questions that involved the electron-pushing (curved arrow) formalism (EPF), part of organic chemistry's language. We analyzed students' answers to two question types on midterms and final exams: (1) draw the electron-pushing arrows of a reaction step, given the starting materials and products; and (2) draw the products of a reaction step, given the starting materials and electron-pushing arrows. For both question types, students were given unfamiliar reactions. The goal was for students to gain proficiency—or fluency—using and interpreting the EPF. By first becoming fluent, students should have lower cognitive load demands when learning subsequent concepts and reactions, positioning them to learn more deeply. Students did not typically draw reversed or illogical arrows, but there were many other error types. Scores on arrows questions were significantly higher than on products questions. Four factors correlated with lower question scores, including: compounds bearing implicit atoms, intramolecular reactions, assessment year, and the conformation of reactants drawn on the page. We found little evidence of analysis strategies such as expanding or mapping structures. We also found a new error type that we describe as picking up electrons and setting them down on a different atom. These errors revealed the difficulties that arose even before the students had to consider the chemical meaning and implications of the reactions. Herein, we describe our complete findings and suggestions for instruction, including videos that we created to teach the EPF.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.006 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it