The paper presents the design and evaluation of a voluntary online introductory stoichiometry (VOIS) course aimed at facilitating the transition from secondary to higher education. The course utilized simple analogies and adaptive feedback through a formative scaffolding assessment. The study assessed the effectiveness of the VOIS course through pre- and post-knowledge tests, analysis of students' performance in general chemistry, and course evaluation surveys conducted at a Latin American University between 2019 and 2021. A total of 3995 first-year STEM students enrolled in the course voluntarily, and 358 students successfully completed it. The results showed a statistically significant improvement in stoichiometry-related knowledge, with the pre–post test scores increasing from 4.61 to 6.55 out of 10. The matched sample analysis, which only included students with 100% participation, demonstrated a statistically significant improvement in stoichiometry and related knowledge from 5.31 to 6.61. Furthermore, an analysis comparing the performance of students who completed the VOIS course with those who didn't reveal that the former group outperformed the latter by an average of 10.6 points in the general chemistry course. This statistically significant difference exhibited a large effect size (d = 0.8). In addition, a matching technique was employed to construct a synthetic control group in order to reduce bias in the quasi-experimental design. A successful propensity score analysis was conducted, controlling for variables such as gender, grade in high school, scores in the national test, and student ranking in their high school. The results of this analysis showed a statistically significant improvement of 8.6 points in the general chemistry performance for students who completed the VOIS course compared to those who did not enroll in the course. Furthermore, the feedback from 129 respondents indicated that 80% of the students either liked the VOIS course or liked it very much, with an overall satisfaction rating of 3.1 on a four-point scale. In conclusion, the VOIS course demonstrated positive outcomes in terms of enhanced stoichiometry knowledge, academic performance, and student satisfaction. These findings highlight the potential of online courses like VOIS in facilitating the transition to higher education.

中文翻译：

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针对 STEM 大学生一年级学生的化学计量自愿在线课程的设计和影响

本文介绍了自愿在线化学计量学入门（VOIS）课程的设计和评估，旨在促进中等教育向高等教育的过渡。该课程通过形成性脚手架评估利用简单的类比和适应性反馈。该研究通过课前和课后知识测试、学生普通化学表现分析以及2019年至2021年间在拉丁美洲大学进行的课程评估调查，评估了VOIS课程的有效性。共有3995名一年级STEM学生学生自愿报名该课程，已有358名学生成功完成课程。结果显示，化学计量相关知识有统计学上的显着改善，前后测试分数从 4.61 提高到 6.55（满分 10）。匹配样本分析（仅包括 100% 参与的学生）显示化学计量有统计学上的显着改善以及5.31至6.61的相关知识。此外，一项对完成 VOIS 课程的学生与未完成 VOIS 课程的学生的表现进行比较的分析显示，前者在普通化学课程中的表现平均比后者高出 10.6 分。这种统计上显着的差异表现出很大的效应量（d = 0.8）。此外，采用匹配技术构建合成对照组，以减少准实验设计中的偏差。我们成功进行了倾向得分分析，控制了性别、高中成绩、国家考试成绩以及高中学生排名等变量。分析结果显示，与未参加该课程的学生相比，完成 VOIS 课程的学生的一般化学成绩显着提高了 8.6 分。此外，129 名受访者的反馈表明，80% 的学生喜欢或非常喜欢 VOIS 课程，总体满意度为 3.1（四分制）。总之，VOIS 课程在增强化学计量知识、学习成绩和学生满意度方面表现出了积极的成果。这些发现凸显了 VOIS 等在线课程在促进向高等教育过渡方面的潜力。