Field M.
Watts
a,
Solaire A.
Finkenstaedt-Quinn
b and
Ginger V.
Shultz
*b
aDepartment of Chemistry & Biochemistry, University of Wisconsin – Milwaukee, Milwaukee, WI 53211, USA
bDepartment of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA. E-mail: gshultz@umich.edu
First published on 27th March 2024
Research on student learning in organic chemistry indicates that students tend to focus on surface level features of molecules with less consideration of implicit properties when engaging in mechanistic reasoning. Writing-to-learn (WTL) is one approach for supporting students’ mechanistic reasoning. A variation of WTL incorporates peer review and revision to provide opportunities for students to interact with and learn from their peers, as well as revisit and reflect on their own knowledge and reasoning. However, research indicates that the rhetorical features included in WTL assignments may influence the language students use in their responses. This study utilizes machine learning to characterize the mechanistic features present in second-semester undergraduate organic chemistry students’ responses to two versions of a WTL assignment with different rhetorical features. Furthermore, we examine the role of peer review on the mechanistic reasoning captured in students’ revised drafts. Our analysis indicates that students include both surface level and implicit features of mechanistic reasoning in their drafts and in the feedback to their peers, with slight differences depending on the rhetorical features present in the assignment. However, students’ revisions appeared to be primarily connected to the peer review process via the presence of surface features in the drafts students read (as opposed to the feedback received). These findings indicate that further scaffolding focused on how to utilize information gained from the peer review process (i.e., both feedback received and drafts read) and emphasizing implicit properties could help support the utility of WTL for developing students’ mechanistic reasoning in organic chemistry.
For the present article, we focus on the mechanistic framework originally described by Machamer et al. (2000) and elaborated upon by Russ et al. (2008). The framework focuses on how students explain phenomena by accounting for the underlying entities, the activities they undergo to effect change, and the properties of entities which guide the activities (Machamer et al., 2000; Russ et al., 2008). This framework has been operationalized in the context of the organic chemistry education research literature with the understanding that entities are the electrons, atoms, and molecules involved in a given reaction; that activities are the movements of electrons which involve the breaking and making of bonds; and that properties of entities include the chemical properties such as basicity or nucleophilicity which provide explanations for why entities interact in predictable ways (Caspari et al., 2018b; Keiner and Graulich, 2020, 2021; Watts et al., 2020). Previous research in organic chemistry settings has used this framework to characterize student responses to WTL assignments (Watts et al., 2020), case comparisons (Caspari et al., 2018a), and tasks intended to support students with connecting laboratory procedures to particulate-level explanations of phenomena (Keiner and Graulich, 2020, 2021).
A review of studies on students’ mechanistic reasoning in organic chemistry indicates that a prominent theme involves the dichotomy between students’ focus on surface features and implicit properties when explaining why reactions occur (Dood and Watts, 2023). In this context, reasoning based on surface features has been previously defined as justifying the result of a given chemical transformation by focusing on the explicit properties of interacting entities. For example, a common finding in the literature is that students often explain why molecules interact by focusing on formal charges (which are an explicit property, since they are visible on the page when drawing a reaction mechanism; Anzovino and Lowery Bretz, 2015; Galloway et al., 2017; Finkenstaedt-Quinn et al., 2020a, 2020b; Petterson et al., 2020). In other words, reasoning based on surface features tends to focus more on a descriptive explanation of what occurs during a reaction without appealing to the underlying, implicit chemical properties. In contrast, reasoning based on implicit properties utilizes the chemical properties of interacting species to guide the explanation of a given transformation; these chemical properties, such as basicity or nucleophilicity, are considered implicit and require students to access their chemistry knowledge (Strickland et al., 2010; Cartrette and Mayo, 2011; Cruz-Ramírez de Arellano and Towns, 2014; Anzovino and Bretz, 2016; Wilson and Varma-Nelson, 2019; Deng and Flynn, 2021). Reviews of the literature on students’ reasoning in organic chemistry demonstrate that students are capable of reasoning about reaction mechanisms using both surface features and implicit properties (Dood and Watts, 2022, 2023). Supporting students with moving from focusing on surface features towards engaging in reasoning about implicit properties is one of the central goals of many novel assessments and interventions in organic chemistry instruction, including the WTL assignments central to this study.
The MWrite program combines both the elements of effective WTL and the benefits of peer review by working with instructors to develop WTL assignments in which students submit initial drafts in response to a contextualized prompt, undergo content-focused peer review, and submit revised drafts (Finkenstaedt-Quinn et al., 2021a). We have studied how students respond to these assignments across a series of disciplines (e.g., materials science, biology, statistics) and courses (e.g., general chemistry, organic chemistry, introductory physical chemistry); an analysis across our studies indicates that the assignments successfully engage students with the targeted content (Finkenstaedt-Quinn et al., 2023). Specifically, analyses of students’ drafts indicate that these assignments support students with describing challenging concepts, applying their content knowledge, and engaging in complex reasoning in various STEM courses, including introductory organic chemistry courses (e.g., Finkenstaedt-Quinn et al., 2017, 2020a; Watts et al., 2020; Brandfonbrener et al., 2021). In addition, examination of students’ revisions and peer review comments indicates that students constructively participate in the peer review and revision processes associated with these assignments (e.g., Halim et al., 2018; Finkenstaedt-Quinn et al., 2019, 2020a, 2021b).
The present study seeks to extend our understanding of how students engage with WTL, specifically in the context of a second-semester organic chemistry WTL assignment intended to support students’ mechanistic reasoning. In our prior work focused on WTL in an organic chemistry course context, we examined how the assignments could support students’ mechanistic reasoning, understanding of acid–base chemistry, and representational competence (Schmidt-McCormack et al., 2019; Watts et al., 2020, 2022a, 2022b; Finkenstaedt-Quinn et al., 2024). Through qualitative and quantitative analysis of students’ drafts, a subset of these studies identified evidence of mechanistic reasoning within students’ responses to WTL assignments in alignment with the aforementioned mechanistic reasoning framework (Russ et al., 2008; Watts et al., 2020, 2022a). In another study, we identified that students’ revisions to a WTL assignment were largely influenced by the drafts they read during the peer review process, and that the peer review comments received were more influential for students who demonstrated inaccurate chemical reasoning (Watts et al., 2022b). Additionally, we have identified that students engage with peer review to different degrees, and that specific features of the drafts students read or the comments received can be connected to specific revisions identifiable within students’ writing (Finkenstaedt-Quinn et al., 2024).
In addition to the importance of peer review and revision, the research on WTL also indicates the importance of the rhetorical aspects of the assignments, which include providing a context for the writing task, an audience for students to write to, and a genre to guide how students structure their response (Gere et al., 2019). Specifically, studies capturing students’ experiences with the assignments in organic chemistry demonstrate how the context provided in the assignments can support students to make connections between concepts and support their affect about the assignments (Gupte et al., 2021; Petterson et al., 2022; Zaimi et al., 2024). Furthermore, students described the audience and genre as influencing both the language they used and the amount of target content they included in their responses (Gupte et al., 2021; Petterson et al., 2022; Zaimi et al., 2024). One of these studies found that different rhetorical contexts (e.g., a grant proposal vs. a news article) can pose challenges for students when the rhetorical aspects are misaligned with the learning goals (Zaimi et al., 2024). Because the presence of rhetorical features requires students to balance the level of detail provided in their response with the expectations for a given audience and genre, it is necessary to investigate how the presence of rhetorical features influences students’ responses and revisions throughout the WTL process.
The goal of the present study is to further investigate the nature of students’ writing and revisions, as influenced by the rhetorical aspects of an assignment and the peer review process, in the context of mechanistic reasoning. Specifically, we employ previously developed machine learning (ML) models (Watts et al., 2022a) to automatically analyze the evidence of mechanistic reasoning present in students’ responses to two variations of the same WTL assignment and to identify students’ revisions at the sentence level. We additionally use a similar ML approach to analyze students’ peer review comments at scale in order to quantitatively investigate the influence of the peer review process on students’ revisions. By leveraging ML methods, this work demonstrates the value of combining automated analysis with human interpretation to facilitate insights related to learning environments (Martin and Graulich, 2023). Specifically, this study not only replicates findings from prior research by analyzing the peer review process at a larger scale, but also provides nuance and improved understanding on the way assignment design and peer review influence students’ writing about organic chemistry reaction mechanisms.
In the context of this study, the assignment prompt (and the included chemical structures), peer review criteria, and revision guidelines are artifacts that serve as representations of what students should be considering as they respond to the assignment. Furthermore, their peers’ drafts that they read and the peer feedback they receive are artifacts that serve as external representations of their peers’ knowledge or understanding on the topic covered by the assignment. As students engage in the process of writing, they create an initial response based on how they interpret the assignment prompt and their existing knowledge on the topic. Then, they engage with the artifacts resulting from the scaffolded social interactions of the peer review process. As students revise, they can reflect on their understanding of the assignment, the target content, and how to present the content. With the significance of the task environment for guiding students’ responses, it is important to consider how changes to the task environment (e.g., different assignment prompts) may result in differences to both students’ initial responses and how they interact with their peers’ artifacts. Considered together, distributed cognition supports our thinking on how students can draw knowledge from both their peers and artifacts related to the assignment while the cognitive process theory of writing demonstrates how that knowledge can be used and incorporated into their final draft for the assignment. Furthermore, both theories indicate that students’ written artifacts can serve as external representations of students’ knowledge about a topic.
1. What are the differences between students’ initial and revised drafts for their written explanations of reaction mechanisms for two versions of the same WTL assignment (one with rhetorical components and one without)?
2. How are students’ revised drafts influenced by peer review (both receiving feedback and reading peer responses) in the context of the two versions of the WTL assignment?
After providing context by discussing the interest in using thalidomide to treat nausea in cancer patients, the assignment discussed the desire to develop an analog of thalidomide that would prevent both racemization and hydrolysis. The writing task involved asking students to explain the mechanisms for both reactions and to propose a thalidomide analog. For this study, we focused on the component of the assignment wherein students were asked to explain the mechanisms. The text for this component of the assignment stated,
“Provide thorough descriptions of the mechanisms of both racemization and acid hydrolysis, highlighting the critical structural features of thalidomide and their role in these mechanisms.
a. When racemization occurs, what changes occur in the molecule?
b. When hydrolysis occurs, what changes occur in the molecule?”
There were two versions of the assignment with rhetorical differences. The central writing tasks (i.e., describing the mechanisms and proposing an analog) remained the same between versions. The difference between the assignments related to the rhetorical framing of the prompt, specifically whether or not students were given a role, a specific audience, and a genre. In the traditional version, the assignment indicated that,
“You are an OB-GYN at the Mayo Clinic. A colleague, who is an oncologist at the University of Minnesota, has approached you about a potential collaboration on a human clinical trial… As an organic expert in the chemical pathways that lead to birth defects, you are writing an email to your collaborator. Your goal will be to propose a structural difference that will make the thalidomide analog unreactive toward both racemization and hydrolysis. You must provide descriptions of the structure and reactivity of thalidomide toward racemization and hydrolysis as well as descriptions of the structural differences in the proposed analog that will make it unreactive to both of these processes. The oncologist is not an expert in organic chemistry. Therefore, carefully consider which organic chemistry terms to use and when to define or explain them. Use clear and concise language, striking a balance between organic jargon and oversimplified explanations.” – Full (italics added).
In contrast, the other version indicated that,
“An OB-GYN at the Mayo Clinic and an oncologist at the University of Minnesota are exploring a potential collaboration on a human clinical trial… Your assignment is to propose a structural difference that will make the thalidomide analog unreactive toward both racemization and hydrolysis. You must provide descriptions of the structure and reactivity of thalidomide toward racemization and hydrolysis as well as descriptions of the structural differences in the proposed analog that will make it unreactive to both of these processes.” – Pared (italics added).
The goal of implementing the two versions of the assignment was to investigate the influence of rhetorical aspects on the specificity of students’ writing, specifically with respect to features related to mechanistic reasoning. Investigating these differences will provide insight regarding how the learning goals of the WTL assignment interact with the rhetorical aspects, which are in place to make the writing task meaningful (Finkenstaedt-Quinn et al., 2021a). The full text for both versions of the assignment are provided in Appendix 1. Hereafter, the two assignment versions will be referred to as the full and pared versions, respectively.
The assignment was the first of three implemented in the course. In addition to the meaning-making task in which students were expected to describe and explain the thalidomide mechanisms, the WTL implementation included additional structures to support students’ learning with WTL (i.e., to provide clear expectations, include opportunities for interactive writing, and promote metacognition; Bangert-Drowns et al., 2004; Anderson et al., 2015; Gere et al., 2019). Specifically, the assignment was provided in the learning management system alongside the evaluation rubric to clarify expectations. Students were given either the full or pared version of the assignment depending on the lecture section of the course in which they were enrolled. Students then had one week to write and submit their first drafts, after which they underwent peer review as a form of interactive writing. The peer review process was automated and double-blind, and students typically gave and received feedback to/from three of their peers within the same lecture section. Peer review entailed responding to content-focused criteria developed to elicit constructive feedback focused on the concepts within the assignment rather than the grammar or style of students’ writing; the peer review criteria relevant to this study are included in Table 1, and the remaining criterion is provided in Appendix 1. Following peer review, students had three days to revise their response, which provided an opportunity for metacognition wherein students could reflect on what they incorporated into their initial response, and why, by considering the peer review feedback received and the responses they read during peer review.
How well does the author explain the process of racemization in thalidomide? Suggest some ways that the author could improve their mechanism description, including discussing what changes occur in the thalidomide molecule through the racemization mechanism. |
How well does the author explain the process of hydrolysis in thalidomide? Suggest some ways that the author could improve their mechanism description, including discussing what changes occur in the thalidomide molecule through the hydrolysis mechanism. |
The model which identified whether individual sentences in a response contained text relevant to a mechanistic explanation was trained using 3027 sentences which either included (n = 1243) or did not include (n = 1784) descriptions of mechanisms. The data was split into 67.5%, 22.5%, and 10% sets for training, validation, and testing respectively. The training and validation sets were used to train a convolutional neural network which performed with 88.6% accuracy and 0.762 Cohen's κ on the testing set; these human-machine agreement values were deemed acceptable due to being above the recommended value of κ > 0.70 for using ML in assessment (Williamson et al., 2012). After identifying sentences with relevant text, we used a set of previously reported ML models to identify the presence of specific mechanistic reasoning features (Watts et al., 2022a). The models capture features necessary for mechanistic reasoning, originally derived from Russ et al.'s (2008) framework for discourse analysis for capturing students’ mechanistic descriptions and explanations; the alignment between the ML models and the Russ et al. framework is shown in Fig. 4. The priorly reported models exhibited strong performance with accuracies and Cohen's κ between 88.4–99.7% and 0.738–0.993, respectively (Watts et al., 2022a). Using this analysis process, we automatically evaluated the presence of mechanistic reasoning features in students’ responses to both versions of the assignment.
Next, we performed statistical analyses to investigate differences between responses for the two versions of the WTL assignment. We first conducted chi-square tests of independence to determine whether student responses differed between the full versus pared assignments; the chi-square tests of independence specifically sought to identify differences in whether students incorporated the mechanistic reasoning features at least once in their response (Sheskin, 2011). We then sought to compare the frequency with which students included each mechanistic reasoning feature. We conducted Shapiro-Wilk tests and determined that the distributions for the total number of sentences and for the number of sentences including each feature were non-normally distributed; as such, we used Mann–Whitney U tests to compare the frequency with which features appeared between groups. The distributions for the number of relevant sentences were normally distributed, so these were compared using t-tests (Sheskin, 2011). The analyses involved comparing between the full and pared prompt for both students’ initial and revised drafts, along with comparing between students’ initial and revised drafts for each version of the prompt. For all statistical analyses, we set alpha = 0.05 and corrected p-values using Bonferroni's method to account for family-wise Type 1 error rates (Sheskin, 2011). To calculate effect sizes, we used phi for the chi-square tests of independence, r for the Mann–Whitney U tests, and Cohen's d for the t-tests (Fritz et al., 2012).
Code | Definition | Exemplars | Human–human agreement measures | Machine learning model | Human–computer agreement measures | ||
---|---|---|---|---|---|---|---|
% | κ | % | κ | ||||
Charge | The peer review comment included mention of the formal charges (i.e., positive, negative, or neutral charge) of atoms or molecules. | “Good explanation of the hydrolysis reaction in thalidomide however it could be more detailed including details on what causes the molecule to split (the nitrogen being positively charged)….” | 98.5 | 0.935 | Convolutional neural network | 96.5 | 0.803 |
Implicit properties | The peer review comment included mention of implicit properties (i.e., acidity/basicity, nucleophilicity/electrophilicity, electronegativity, resonance, etc.). | “…In my mechanism of racemization, I had a few more steps (I started with a protonation of the carbonyl, making the carbon of the carbonyl more electrophilic, then I did the deprotonation of the stereocenter's hydrogen, and formed the double bond), but I'm not sure whether mine is completely correct, so take that with a grain of salt…” | 95.5 | 0.831 | SciBERT model | 96.0 | 0.829 |
Other | The peer review comment included anything else. | “The racemization is hinted at through the considerations of the R and S enantiomers. To improve the mechanism description, it may be beneficial to describe the steps of racemization, instead of stating that both enantiomers are produced…” | 96.5 | 0.910 | Convolutional neural network | 97.0 | 0.910 |
After coding the initial 1010 peer review comments, we trained three ML models (one for each code) to automatically analyze the remaining peer review comments in the dataset. To train the ML models, we randomly split the 1010 human-analyzed peer review comments into a training and testing dataset using a 64% training, 16% validation, and 20% testing split. We evaluated the performance of several traditional ML algorithms (naive Bayes, linear regression, support vector machines) and deeper ML algorithms (convolutional neural networks and transformer models). The models with the highest human–computer agreement measures on the testing set were then used for further analysis (see Table 2). All models used for further analysis exhibited human–computer agreement measures with near-perfect agreement and exceeded the recommended value of κ > 0.70 for using ML models for automated assessment (Williamson et al., 2012). With these models, we automatically analyzed the remaining peer review comments, for a total of 3774 comments analyzed (1808 from students providing feedback to the full version of the prompt; 1966 from students providing feedback to the pared version of the prompt). We then conducted chi-square tests of independence to identify whether the frequency with which students commented on different features differed between students responding to the full or pared versions of the assignment, correcting the p-values using Bonferroni's method (Sheskin, 2011).
Fig. 5 Percentages of students incorporating each mechanistic reasoning feature within their response, compared between the full and pared versions of the prompt for students’ initial drafts (left) and revised drafts (right). Tabular results are provided in Appendix 2, Table 6. ** p < 0.01. |
Next, we used Mann–Whitney U tests to compare the frequency of sentences in which students included each mechanistic reasoning feature between the two versions of the assignment (Fig. 6). From this comparison, we identified significant differences between the full and pared version of the assignment for the number of sentences in which students included charges, non-electronic mechanisms, and implicit properties for both the initial and revised drafts. For each of these features, students who responded to the pared version of the prompt included more sentences in their writing, with small effect sizes (r ranging from −0.135 to −0.222). Notably, there was not a significant difference between the total number of sentences or for the total number of relevant sentences for the two versions of the prompt, for both the initial and revised drafts (p = 1.000 and p = 1.000 for total number of sentences and p = 0.133 and p = 0.124 for total number of relevant sentences, for initial and revised drafts, respectively).
Fig. 6 The distribution of the number of sentences for each mechanistic reasoning feature, compared between the full and pared versions of the prompt for students’ initial drafts (left) and revised drafts (right). Tabular results are provided in Appendix 2, Table 7. *p < 0.05, **p < 0.01, ***p < 0.001. |
In addition to comparing between the full and pared versions of the assignment, we also ran a parallel analysis comparing students’ initial and revised drafts for both the full version of the assignment (Fig. 7a and c) and the pared version of the assignment (Fig. 7b and d). These comparisons indicate that, for both versions of the prompt, more students included charges and electron movement within their response upon revision (Fig. 7a and b), with trivial effect sizes (see Appendix 2, Table 8). Additionally, for both assignments, students included significantly more sentences for the same set of mechanistic reasoning features: connectivity, charges, stereochemistry, electron movement, non-electronic mechanisms, and bond breaking/making (Fig. 7c and d), with small effect sizes (see Appendix 2, Table 9).
Fig. 7 Comparison between students’ initial and revised drafts for the full version of the assignment (a) and (c) and the pared version of the assignment (b) and (d); for each assignment version, comparisons between the percentage of students including each feature (a) and (b) and the frequency of sentences in which each feature appeared (c) and (d) are shown. Tabular results are provided in Appendix 2, Tables 8 and 9. *p < 0.05, **p < 0.01, ***p < 0.001. |
Considering both perspectives of the data, the primary findings with respect to research question one are that (1) more students include charges at least once in their initial response to the pared version of the prompt and (2) students include more sentences describing charges, non-electronic mechanisms, and implicit properties for both their initial and revised drafts in response to the pared version of the prompt. However, when comparing between initial and revised drafts for each prompt, the trends are similar between the two prompts, in that students included significantly more sentences for several of the same mechanistic reasoning features upon revision. Although the effect sizes for significant differences were small, we would not necessarily expect large effect sizes due to the minor variation between the prompts.
To address this research question, we first analyzed students’ peer review comments, and then conducted linear regressions to identify the influence of different aspects of peer review on students’ revisions. First, the frequency with which each feature was commented on within the peer review process is provided in Table 3. As indicated within the table, students were significantly more likely to comment on charges when responding to the pared prompt compared to the full prompt. However, for both versions of the prompts, significantly more comments focused on implicit properties with small effect sizes (Table 3).
Feature | Frequency of comments pertaining to each feature | p-Value (between full and pared) | Effect size (phi) | ||
---|---|---|---|---|---|
Full (N = 1808) | Pared (N = 1966) | All (N = 3774) | |||
Charge | 153 comments (8.5%) | 262 comments (13.3%) | 415 comments (11.0%) | <0.001*** | 0.077 |
Implicit properties | 229 comments (12.7%) | 301 comments (15.3%) | 530 comments (14.0%) | 0.155 | 0.037 |
Both charge and implicit properties | 43 comments (2.4%) | 86 comments (4.4%) | 129 comments (3.4%) | 0.007** | 0.053 |
Other | 1469 comments (81.3%) | 1489 comments (75.7%) | 2958 comments (78.4%) | <0.001*** | 0.066 |
p-Value (between charge and implicit properties) | <0.001*** | <0.001*** | <0.001*** | ||
Effect size (phi) | 0.138 | 0.189 | 0.171 |
After characterizing the peer review comments, we performed linear regressions to investigate the relationship between peer review and students’ revised drafts. The two sequential linear regressions are provided for each feature of interest (charges and implicit properties) in Tables 4 and 5, respectively. Descriptive statistics for the variables included in the linear regressions are provided in Appendix 2, Table 10.
Dependent variable | Revised drafts – charges (charges_d2) | Model 1a coeff. (st. err.) | Model 1b coeff. (st. err.) | Model 1c coeff. (st. err.) | Model 1d coeff. (st. err.) | Model 1e coeff. (st. err.) |
---|---|---|---|---|---|---|
*p < 0.05, **p < 0.01, ***p < 0.001. | ||||||
Independent variables | Prompt version (prompt_dummy) | −0.9586 (0.239)*** | −0.2271 (0.160) | −0.2038 (0.162) | −0.0907 (0.164) | −0.0985 (0.165) |
Initial drafts – charges (charges_d1) | — | 0.7564 (0.027)*** | 0.7518 (0.027)*** | 0.7541 (0.027)*** | 0.7579 (0.028)*** | |
Peer review comments – charges (charges_pr) | — | — | 0.0926 (0.095) | 0.0941 (0.094) | 0.0991 (0.099) | |
Drafts read – charges (charges_dr) | — | — | — | 0.3205 (0.098)** | 0.3827 (0.110)** | |
Initial drafts – implicit properties (implicit_d1) | — | — | — | — | −0.0218 (0.037) | |
Peer review comments – implicit properties (implicit_pr) | — | — | — | — | −0.0023 (0.089) | |
Drafts read – implicit properties (implicit_dr) | — | — | — | — | −0.1294 (0.108) | |
Intercept | 5.0815 (0.166)*** | 1.9801 (0.155)*** | 1.9229 (0.166)*** | 1.2089 (0.274)*** | 1.3770 (0.305)*** | |
R-Squared | 0.026 | 0.576 | 0.576 | 0.584 | 0.585 |
Dependent variable | Revised drafts – implicit properties (implicit_d2) | Model 2a coeff. (st. err.) | Model 2b coeff. (st. err.) | Model 2c coeff. (st. err.) | Model 2d coeff. (st. err.) | Model 2e coeff. (st. err.) |
---|---|---|---|---|---|---|
*p < 0.05, **p < 0.01, ***p < 0.001. | ||||||
Independent variables | Prompt version (prompt_dummy) | −0.7122 (0.191)*** | −0.1544 (0.128) | −0.1591 (0.128) | −0.1535 (0.128) | −0.1458 (0.133) |
Initial drafts – implicit properties (implicit_d1) | — | 0.7739 (0.028)*** | 0.7814 (0.029)*** | 0.7815 (0.029)*** | 0.7806 (0.029)*** | |
Peer review comments – implicit properties (implicit_pr) | — | — | −0.0624 (0.068) | −0.0613 (0.068) | −0.0461 (0.071) | |
Drafts read – implicit properties (implicit_dr) | — | — | — | 0.0381 (0.078) | −0.0005 (0.087) | |
Initial drafts – charges (charges_d1) | — | — | — | — | −0.0036 (0.022) | |
Peer review comments – charges (charges_pr) | — | — | — | — | −0.0540 (0.079) | |
Drafts read – charges (charges_dr) | — | — | — | — | 0.0900 (0.088) | |
Intercept | 3.0125 (0.132)*** | 0.9044 (0.115)*** | 0.9427 (0.122)*** | 0.8643 (0.201)*** | 0.7923 (0.245)** | |
R-Squared | 0.022 | 0.574 | 0.575 | 0.575 | 0.576 |
For the set of regressions focused on charges (Table 4), the only two significant independent variables across the five models are charges_d1 and charges_dr. The first significant variable, charges_d1, indicates that the frequency of sentences related to charges in a student’s initial draft is a significant predictor of the student including additional sentences related to charges in their revised draft. The second significant variable, charges_dr, indicates that, in terms of the influence of the peer review process, the frequency of drafts read which included charges significantly influences students’ revisions to include more sentences with charges. The version of the prompt (prompt_dummy), the frequency of peer review comments related to charges (charges_pr), and the independent variables related to implicit properties (implicit_d1, implicit_pr, implicit_dr) did not significantly influence the frequency of sentences pertaining to charges in students’ revisions.
The set of regression models focused on implicit properties are presented in Table 5. As indicated in Table 5, the only feature which significantly predicted the inclusion of sentences pertaining to implicit properties in students’ revisions (implicit_d2) was the frequency with which students included sentences pertaining to implicit properties in their initial draft (implicit_d1). None of the other variables, including the frequency of comments or drafts read relating to implicit properties during the peer review process (implicit_pr, implicit_dr), the variables related to charges (charges_d1, charges_pr, charges_dr), or the version of the prompt (prompt_dummy) significantly predicted the frequency with which students included implicit properties in their revisions.
Considering the analyses pertaining to our second research question, we saw that (1) students gave more feedback related to implicit properties than charges for both versions of the assignment and (2) students commented more on charges in response to the pared version of the assignment compared to the full version. When examining the results of the regressions, we identified that (1) the frequency of sentences including charges in students’ initial draft and the discussion of charges in the drafts they read served as predictors for students’ revisions to incorporate additional sentences with charges, but (2) the frequency of sentences including implicit properties in their initial draft was the only predictor for students’ revisions to incorporate additional sentences with implicit properties in their revised drafts.
The differences between students’ responses to the two versions of the WTL assignment pertain to features of mechanistic reasoning that reflect both surface-level (i.e., charges and non-electronic mechanistic descriptions) and deeper (i.e., implicit properties) reasoning, perhaps suggesting that students responding to the pared version of the prompt included slightly more detailed mechanistic explanations in general relative to students responding to the full version of the prompt. Prior studies indicate that the audience can influence the degree of students’ exhibited knowledge; for example, students in a statistics course exhibited different degrees of explanation for an assignment in which the audience was their grandparents in comparison to an assignment in which the audience was a sports team trainer (Gere et al., 2018). The present study extends our understanding of the interaction between rhetorical aspects of WTL assignments and the learning goals for assignments to promote students’ reasoning by presenting a direct comparison where the rhetorical situation of the assignment differed by altering only nine sentences (out of 38) between the two versions of the assignment. Specifically, the assignment versions differed only in that the full version included an explicitly stated audience and role for the students to assume, whereas the pared version removed the explicit references to the rhetorical situation. The small but significant differences in students’ responses to such small variations demonstrate how minor differences in prompting may guide students to go into more or less mechanistic detail (e.g., by only writing for the implicit audience of their instructor, students responding to the pared prompt did not have to balance mechanistic detail with understandability for a target audience). This finding aligns with how the audience, as part of the task environment, is thought to influence the writing process as described by the cognitive process theory of writing (Flower and Hayes, 1981; Hayes, 1996). The differences in students’ responses extends the findings from prior studies on writing pedagogies in STEM courses in which students described how balancing content expectations for different audiences (e.g., the audience given in the assignment vs. the instructor or grader) posed them challenges (Gere et al., 2018; Gupte et al., 2021; Finkenstaedt-Quinn, Garza, et al., 2022a; Zaimi et al., 2024). Furthermore, while the observed differences between responses to the assignment versions might be small (e.g., a difference of one sentence), the cognitive process theory of writing supports the notion that such differences may reflect increased engagement with the specific ideas that represent students’ understanding of the assignment content (Flower and Hayes, 1981; Hayes, 1996).
Research question two sought to further investigate the role of the peer review process on students’ revisions pertaining to charges and implicit properties specifically. These two features appeared with different frequencies between students’ responses for the two versions of the prompt, although the two features appeared relatively infrequently overall (representing 11–14% of comments received across both assignment versions). We found that students commented upon implicit properties more often than charges for both versions of the assignment. This suggests that even when students emphasize charges (which reflect surface-level reasoning; e.g., Anzovino and Lowery Bretz, 2015; Galloway et al., 2017) in their own responses, they can provide feedback to their peers related to implicit properties (which reflects deeper reasoning; e.g., Anzovino and Bretz, 2016; Deng and Flynn, 2021). Other studies on WTL and peer review in chemistry have demonstrated similar findings, where examination of the comments students provided their peers indicates that they can provide feedback on higher order concepts (Moon et al., 2018b; Finkenstaedt-Quinn et al., 2019, 2020a, 2024). Additionally, students commented on charges more often for the pared version than the full version, suggesting a similar trend related to the role of the audience as identified by examining students’ responses for research question one.
To investigate which aspects of the entire WTL peer review process influenced students’ revisions, we performed regression analyses with the frequency of sentences pertaining to each feature (charges or implicit properties) in students’ revisions as the dependent variable and the prompt, frequency of sentences in students’ initial drafts, frequency of peer review comments received, and frequency of drafts read pertaining to each feature as independent variables. The findings from the regressions indicated no apparent differences between the two versions of the prompt for students’ engagement in peer review. Additionally, for both charges and implicit properties, the most important independent variable for predicting the frequency of sentences related to each feature within students’ revisions was whether the feature was included in students’ initial drafts. However, the two regressions indicated nuanced differences between the two features with respect to the influence of the peer review process on revisions. Specifically, for charges, students’ revisions were also significantly influenced by the number of drafts read which included charges; this finding corroborates prior research examining students’ responses to WTL assignments which indicates that reading drafts and forming feedback often plays a more significant role in students' revisions compared to receiving peer review comments (Finkenstaedt-Quinn et al., 2021b; Watts et al., 2022b). However, the trend was not evident for the implicit properties feature. The finding that the influence of drafts read on revisions may be different for implicit properties furthers our understanding of the WTL process; particularly, it appears that the benefit of reading might be evident for more accessible content (such as charges, which are a surface feature of reaction mechanisms) compared to more challenging content (such as implicit properties, which require deeper reasoning). Additionally, as there was a lower frequency of implicit properties in students’ initial drafts, compared to charges, students may have also gained less exposure to how to incorporate implicit properties into their responses or the importance of implicit properties for mechanistic reasoning. Students’ engagement with aspects of the peer review process may also influence the type and extent of their revisions. In a study examining students’ responses to a similar assignment, Finkenstaedt-Quinn et al. (2024) found that students viewed reading their peers drafts to be more helpful than receiving peer feedback. This distinction may be exacerbated when students consider features related to surface-level versus deeper reasoning. Altogether, viewed through the lens of distributed cognition (Nardi, 1996; Klein and Leacock, 2012), the findings from this study indicate the way students’ knowledge (as represented by their writing) can develop through the process of reading and providing feedback on their peers’ drafts.
This work is also limited by our inability to account for chaining, a key aspect of Russ et al.'s framework for mechanistic reasoning (Russ et al., 2008). Chaining entails reasoning about one step of a mechanism based on what has happened previously (backward chaining) or what will happen next (forward chaining). As discussed in our previous work detailing the development of the analytical framework used in this study (Watts et al., 2020), chaining does not appear distinctly in students’ WTL responses due to the nature of providing a written description when given the opportunity to refer to outside sources and engage in the peer review process. While this precludes us from being able to make claims regarding how students construct a full mechanistic account, the present analysis does allow for us to explore variations in how students incorporate different features of organic reaction mechanisms (such as charges and implicit properties) which reflect how students engage in mechanistic reasoning.
It is understood that thalidomide exists as two enantiomers; one is a teratogen that causes birth defects, while the other has therapeutic properties. Rapid racemization occurs at neutral pH, so both enantiomers are formed at roughly an equal mixture in the blood, which means that, even if only the therapeutic isomer is used, both will form once introduced in the body. The racemization is illustrated below in Fig. 1.
Furthermore, both enantiomers are subject to acid hydrolysis once in the stomach at lower pH, which could produce products that are teratogens. The structure of thalidomide and two thalidomide hydrolysis products are shown below in Fig. 2. For these reasons, it is important to prevent both the racemization and the subsequent hydrolysis of thalidomide.
You are an OB-GYN at the Mayo Clinic. A colleague, who is an oncologist at the University of Minnesota, has approached you about a potential collaboration on a human clinical trial. This trial will propose and test the efficacy of thalidomide analogs for the treatment of nausea in cancer patients. (See note on the third page for an explanation of an analog).
As an organic expert in the chemical pathways that lead to birth defects, you are writing an email to your collaborator. Your goal will be to propose a structural difference that will make the thalidomide analog unreactive toward both racemization and hydrolysis. You must provide descriptions of the structure and reactivity of thalidomide toward racemization and hydrolysis as well as descriptions of the structural differences in the proposed analog that will make it unreactive to both of these processes. The oncologist is not an expert in organic chemistry. Therefore, carefully consider which organic chemistry terms to use and when to define or explain them. Use clear and concise language, striking a balance between organic jargon and oversimplified explanations.
Your email should be approximately between 500–700 words (1–2 pages) in length. It should address the following points:
1. Provide thorough descriptions of the mechanisms of both racemization and acid hydrolysis, highlighting the critical structural features of thalidomide and their role in these mechanisms.
a. When racemization occurs, what changes occur in the molecule?
b. When hydrolysis occurs, what changes occur in the molecule?
2. Propose a thalidomide analog (one compound) that would not undergo racemization or hydrolysis. Explain what structural features are in place that would inhibit or prevent these processes.
You can and should include figures of schemes, structures, or mechanisms, if that supports your response. We suggest that you have the figure(s) in front of you—ready to color-code or mark-up in various ways—and that you use your visible thinking to guide your audience through your explanation. Any images that you include in your response, including the figures in this prompt or those that you draw in ChemDraw or on paper, must have the original source cited using either ACS or APA format. Given your audience, your written response should suffice so that the explanations can be understood without the figures. You will be graded only on your written response.
An analog is a compound that is very similar to but has small structural differences from the pharmaceutical target. For example, m-cresol (shown in Fig. 8 below) is an analog of phenol.
It is understood that thalidomide exists as two enantiomers; one is a teratogen that causes birth defects, while the other has therapeutic properties. Rapid racemization occurs at neutral pH, so both enantiomers are formed at roughly an equal mixture in the blood, which means that, even if only the therapeutic isomer is used, both will form once introduced in the body. The racemization is illustrated below in Fig. 1.
Furthermore, both enantiomers are subject to acid hydrolysis once in the stomach at lower pH, which could produce products that are teratogens. The structure of thalidomide and two thalidomide hydrolysis products are shown below in Fig. 2. For these reasons, it is important to prevent both the racemization and the subsequent hydrolysis of thalidomide.
An OB-GYN at the Mayo Clinic and an oncologist at the University of Minnesota are exploring a potential collaboration on a human clinical trial. This trial will propose and test the efficacy of thalidomide analogs for the treatment of nausea in cancer patients. (See note on the third page for an explanation of an analog).
Your assignment is to propose a structural difference that will make the thalidomide analog unreactive toward both racemization and hydrolysis. You must provide descriptions of the structure and reactivity of thalidomide toward racemization and hydrolysis as well as descriptions of the structural differences in the proposed analog that will make it unreactive to both of these processes.
Your response should be approximately between 500–700 words (1–2 pages) in length. It should address the following points:
1. Provide thorough descriptions of the mechanisms of both racemization and acid hydrolysis, highlighting the critical structural features of thalidomide and their role in these mechanisms.
a. When racemization occurs, what changes occur in the molecule?
b. When hydrolysis occurs, what changes occur in the molecule?
2. Propose a thalidomide analog (one compound) that would not undergo racemization or hydrolysis. Explain what structural features are in place that would inhibit or prevent these processes.
You can and should include figures of schemes, structures, or mechanisms, if that supports your response. We suggest that you have the figure(s) in front of you—ready to color-code or mark-up in various ways—and that you use your visible thinking to guide your explanation. Any images that you include in your response, including the figures in this prompt or those that you draw in ChemDraw or on paper, must have the original source cited using either ACS or APA format. Your written response should suffice so that the explanations can be understood without the figures. You will be graded only on your written response.
An analog is a compound that is very similar to but has small structural differences from the pharmaceutical target. For example, m-cresol (shown in Fig. 8 below) is an analog of phenol.
• Read the essay more slowly keeping the rubric in mind.
• Highlight the pieces of texts that let you directly address the rubric prompts in your online responses.
• In your online responses, focus on larger issues (higher order concerns) of content and argument rather than lower order concerns like grammar and spelling.
• Be very specific in your responses, referring to your peer's actual language, mentioning terms and concepts that are either present or missing, and following the directions in the rubric.
• Use respectful language whether you are suggesting improvements to or praising your peer.
How well does the author explain the process of racemization in thalidomide? Suggest some ways that the author could improve their mechanism description, including discussing what changes occur in the thalidomide molecule through the racemization mechanism.
How well does the author explain the process of hydrolysis in thalidomide? Suggest some ways that the author could improve their mechanism description, including discussing what changes occur in the thalidomide molecule through the hydrolysis mechanism.
Does the author propose a reasonable thalidomide analog that would not undergo racemization or hydrolysis? To what extent does the author explain the specific structural features that are present in the thalidomide analog that would stop racemization and/or hydrolysis from occurring?
Chi-squared tests of independence – D1 full versus D1 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Frequency of responses including each feature | p-Value | Effect size (phi) | |
D1 full (N = 300) | D1 pared (N = 332) | |||
*p < 0.05, **p < 0.01, ***p < 0.001. | ||||
Reaction medium | 211 (70.3%) | 231 (69.6%) | 1.000 | 0.005 |
Connectivity | 285 (95.0%) | 324 (97.6%) | 1.000 | 0.061 |
Charges | 223 (74.3%) | 287 (86.4%) | 0.003** | 0.149 |
Stereochemistry | 293 (97.7%) | 327 (98.5%) | 1.000 | 0.019 |
Electron movement | 225 (75.0%) | 270 (81.3%) | 1.000 | 0.073 |
Non-electronic mechanism | 293 (97.7%) | 329 (99.1%) | 1.000 | 0.045 |
Bond breaking/making | 278 (92.7%) | 314 (94.6%) | 1.000 | 0.033 |
Implicit properties | 224 (74.7%) | 262 (78.9%) | 1.000 | 0.047 |
Stereochemistry formation | 274 (91.3%) | 305 (91.9%) | 1.000 | 0.004 |
Chi-squared tests of independence – D2 full versus D2 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Frequency of responses including each feature | p-Value | Effect size (phi) | |
D2 full (N = 300) | D2 pared (N = 331) | |||
Reaction medium | 223 (74.3%) | 242 (73.1%) | 1.000 | 0.010 |
Connectivity | 297 (99.0%) | 331 (100%) | 1.000 | 0.050 |
Charges | 269 (89.7%) | 313 (94.6%) | 0.574 | 0.085 |
Stereochemistry | 298 (99.3%) | 330 (99.7%) | 1.000 | 0.003 |
Electron movement | 267 (89.0%) | 305 (92.1%) | 1.000 | 0.048 |
Non-electronic mechanism | 299 (99.7%) | 331 (100%) | 1.000 | 0.002 |
Bond breaking/making | 294 (98.0%) | 328 (99.1%) | 1.000 | 0.033 |
Implicit properties | 240 (80.0%) | 286 (86.4%) | 0.726 | 0.082 |
Stereochemistry formation | 286 (95.3%) | 317 (98.5%) | 1.000 | 0.003 |
Mann–Whitney U tests – D1 full versus D1 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Median number of sentences (mean, standard deviation) | p-Value | Effect size (r) | |
D1 full (N = 300) | D1 pared (N = 332) | |||
*p < 0.05, **p < 0.01, ***p < 0.001.a p-Values from t-tests with the Bonferroni correction for multiple hypothesis tests.b Effect sizes for t-tests are Cohen's d. | ||||
Reaction medium | 1 (1.54, 1.45) | 1 (1.55, 1.51) | 1.000 | 0.009 |
Connectivity | 4 (4.66, 3.02) | 5 (5.16, 2.87) | 0.562 | −0.088 |
Charges | 3 (3.15, 2.86) | 4 (4.05. 3.00) | 0.002** | −0.157 |
Stereochemistry | 5 (4.91, 2.46) | 5 (5.24, 2.39) | 1.000 | −0.070 |
Electron movement | 2 (3.10, 3.05) | 3 (3.51, 2.90) | 0.338 | −0.096 |
Non-electronic mechanism | 8 (7.09, 3.60) | 8 (8.39, 3.45) | <0.001*** | −0.175 |
Bond breaking/making | 3 (3.05, 1.84) | 3 (3.28, 2.26) | 1.000 | −0.026 |
Implicit properties | 1 (2.00, 2.03) | 2 (2.70, 2.48) | 0.013* | −0.135 |
Stereochemistry formation | 2 (2.42, 1.48) | 2 (2.33, 1.51) | 1.000 | 0.045 |
Number of sentences | 35 (36.09, 9.54) | 34 (35.13, 8.89) | 1.000 | 0.052 |
Number of relevant sentences | 16 (16.49, 5.65) | 18 (17.68, 5.26) | 0.133a | 0.220b |
Mann–Whitney U tests – D2 full versus D2 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Median number of sentences (mean, standard deviation) | p-Value | Effect size (r) | |
D2 full (N = 300) | D2 pared (N = 331) | |||
Reaction medium | 1 (1.63, 1.45) | 1 (1.67, 1.52) | 1.000 | −0.004 |
Connectivity | 5 (5.58, 2.63) | 6 (6.16, 2.66) | 0.228 | −0.101 |
Charges | 4 (4.14, 2.92) | 5 (5.08, 3.00) | 0.001** | −0.158 |
Stereochemistry | 6 (5.89, 2.45) | 6 (6.15, 2.48) | 1.000 | −0.045 |
Electron movement | 4 (4.06, 2.93) | 4 (4.45, 2.77) | 0.834 | −0.082 |
Non-electronic mechanism | 9 (8.74, 2.98) | 10 (10.20, 2.94) | <0.001*** | −0.222 |
Bond breaking/making | 4 (3.66, 1.78) | 3 (3.70, 1.92) | 1.000 | 0.012 |
Implicit properties | 2 (2.27, 2.09) | 2 (3.05, 2.55) | 0.003** | −0.151 |
Stereochemistry formation | 3 (2.81, 1.61) | 2 (2.63, 1.50) | 1.000 | 0.053 |
Number of sentences | 41 (41.69, 9.47) | 41 (40.85, 9.31) | 1.000 | 0.039 |
Number of relevant sentences | 19 (19.24, 5.18) | 20 (20.34, 4.68) | 0.124a | 0.222b |
Chi-squared tests of independence – D1 full versus D2 full | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Frequency of responses including each feature | p-Value | Effect size (phi) | |
D1 full (N = 300) | D2 full (N = 300) | |||
* p < 0.05, ** p < 0.01, *** p < 0.001. | ||||
Reaction medium | 211 (70.3%) | 223 (74.3%) | 1.000 | 0.041 |
Connectivity | 285 (95.0%) | 297 (99.0%) | 0.153 | 0.107 |
Charges | 223 (74.3%) | 269 (89.7%) | <0.001*** | 0.195 |
Stereochemistry | 293 (97.7%) | 298 (99.3%) | 1.000 | 0.055 |
Electron movement | 225 (75.0%) | 267 (89.0%) | <0.001*** | 0.178 |
Non-electronic mechanism | 293 (97.7%) | 299 (99.7%) | 1.000 | 0.073 |
Bond breaking/making | 278 (92.7%) | 294 (98.0%) | 0.066 | 0.119 |
Implicit properties | 224 (74.7%) | 240 (80.0%) | 1.000 | 0.060 |
Stereochemistry formation | 274 (91.3%) | 286 (95.3%) | 1.000 | 0.073 |
Chi-squared tests of independence – D1 pared versus D2 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Frequency of responses including each feature | p-Value | Effect size (phi) | |
D1 pared (N = 332) | D2 pared (N = 331) | |||
Reaction medium | 231 (69.6%) | 242 (73.1%) | 1.000 | 0.036 |
Connectivity | 324 (97.6%) | 331 (100%) | 0.233 | 0.097 |
Charges | 287 (86.4%) | 313 (94.6%) | 0.011* | 0.133 |
Stereochemistry | 327 (98.5%) | 330 (99.7%) | 1.000 | 0.048 |
Electron movement | 270 (81.3%) | 305 (92.1%) | 0.001** | 0.155 |
Non-electronic mechanism | 329 (99.1%) | 331 (100%) | 1.000 | 0.045 |
Bond breaking/making | 314 (94.6%) | 328 (99.1%) | 0.035* | 0.120 |
Implicit properties | 262 (78.9%) | 286 (86.4) | 0.262 | 0.095 |
Stereochemistry formation | 305 (91.9%) | 317 (95.8%) | 0.976 | 0.075 |
Mann–Whitney U tests – D1 full versus D2 full | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Median number of sentences (mean, standard deviation) | p-Value | Effect size (r) | |
D1 full (N = 300) | D2 full (N = 300) | |||
*p < 0.05, **p < 0.01, ***p < 0.001.a p-Values from t-tests with the Bonferroni correction for multiple hypothesis tests.b Effect sizes for t-tests are Cohen's d. | ||||
Reaction medium | 1 (1.54, 1.45) | 1 (1.63, 1.45) | 1.000 | −0.034 |
Connectivity | 4 (4.66, 3.02) | 5 (5.58, 2.63) | <0.001*** | −0.167 |
Charges | 3 (3.15, 2.86) | 4 (4.14, 2.92) | <0.001*** | −0.176 |
Stereochemistry | 5 (4.91, 2.46) | 6 (5.89, 2.45) | <0.001*** | −0.197 |
Electron movement | 2 (3.10, 3.05) | 4 (4.06, 2.93) | <0.001*** | −0.192 |
Non-electronic mechanism | 8 (7.09, 3.60) | 9 (8.74, 2.98) | <0.001*** | −0.233 |
Bond breaking/making | 3 (3.05, 1.84) | 4 (3.66, 1.78) | <0.001*** | −0.168 |
Implicit properties | 1 (2.00, 2.03) | 2 (2.27, 2.09) | 1.000 | −0.070 |
Stereochemistry formation | 2 (2.42, 1.48) | 3 (2.81, 1.61) | 0.100 | −0.114 |
Number of sentences | 35 (36.09, 9.54) | 41 (41.69, 9.47) | <0.001*** | −0.293 |
Number of relevant sentences | 16 (16.49, 5.65) | 19 (19.24, 5.18) | <0.001***a | 0.508b |
Mann–Whitney U tests – D1 pared versus D2 pared | ||||
---|---|---|---|---|
Mechanistic reasoning feature | Median number of sentences (mean, standard deviation) | p-Value | Effect size (r) | |
D1 pared (N = 332) | D2 pared (N = 331) | |||
Reaction medium | 1 (1.55, 1.51) | 1 (1.67, 1.52) | 1.000 | −0.046 |
Connectivity | 5 (5.16, 2.87) | 6 (6.16, 2.66) | <0.001*** | −0.177 |
Charges | 4 (4.05, 3.00) | 5 (5.08, 3.00) | <0.001*** | −0.171 |
Stereochemistry | 5 (5.24, 2.39) | 6 (6.15, 2.48) | <0.001*** | −0.182 |
Electron movement | 3 (3.51, 2.90) | 4 (4.45, 2.77) | <0.001*** | −0.182 |
Non-electronic mechanism | 8 (8.39, 3.45) | 10 (10.20, 2.94) | <0.001***a | 0.564b |
Bond breaking/making | 3 (3.28, 2.26) | 3 (3.70, 1.92) | 0.012* | −0.132 |
Implicit properties | 2 (2.70, 2.48) | 2 (3.05, 2.55) | 1.000 | −0.075 |
Stereochemistry formation | 2 (2.33, 1.51) | 2 (2.63, 1.50) | 0.132 | −0.104 |
Number of sentences | 34 (35.13, 8.89) | 41 (40.85, 9.31) | <0.001*** | −0.307 |
Number of relevant sentences | 18 (17.68, 5.26) | 20 (20.34, 4.68) | <0.001***a | 0.532b |
Variable | Mean | St. dev. | Min. | Max. |
---|---|---|---|---|
Revised drafts – charges (charges_d2) | 4.623 | 2.995 | 0 | 13 |
Revised drafts – implicit properties (implicit_d2) | 2.672 | 2.381 | 0 | 13 |
Prompt version (prompt_dummy) | 0.479 | 0.500 | 0 | 1 |
Initial drafts – charges (charges_d1) | 3.637 | 2.977 | 0 | 13 |
Peer review comments – charges (charges_pr) | 0.678 | 0.858 | 0 | 4 |
Drafts read – charges (charges_dr) | 2.029 | 0.819 | 0 | 3 |
Initial drafts – implicit properties (implicit_d1) | 2.379 | 2.314 | 0 | 14 |
Peer review comments – implicit properties (implicit_pr) | 0.866 | 0.967 | 0 | 5 |
Drafts read – implicit properties (implicit_dr) | 1.961 | 0.816 | 0 | 3 |
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