Background
Graduate teaching assistants (GTAs) often lead laboratory and tutorial sections in science, technology, engineering, and mathematics (STEM), especially at large, research-intensive universities. GTAs’ performance as instructors can impact student learning experience as well as learning outcomes. In this study, we observed 11 chemistry GTAs and 11 physics GTAs in a research-intensive institution in the southeastern USA. We observed the GTAs over two consecutive semesters in one academic year, resulting in a total of 58 chemistry lab observations and 72 physics combined tutorial and lab observations. We used a classroom observation protocol adapted from the Laboratory Observation Protocol for Undergraduate STEM (LOPUS) to document both GTA and student behaviors. We applied cluster analysis separately to the chemistry lab observations and to the physics combined tutorial and lab observations. The goals of this study are to classify and characterize GTAs’ instructional styles in reformed introductory laboratories and tutorials, to explore the relationship between GTA instructional style and student behavior, and to explore the relationship between GTA instructional style and the nature of laboratory activity.

Results
We identified three instructional styles among chemistry GTAs and three different instructional styles among physics GTAs. The characteristics of GTA instructional styles we identified in our samples are different from those previously identified in a study of a traditional general chemistry laboratory. In contrast to the findings in the same prior study, we found a relationship between GTAs’ instructional styles and student behaviors: when GTAs use more interactive instructional styles, students appear to be more engaged. In addition, our results suggest that the nature of laboratory activities may influence GTAs’ use of instructional styles and student behaviors. Furthermore, we found that new GTAs appear to behave more interactively than experienced GTAs.

Conclusion
GTAs use a variety of instructional styles when teaching in the reformed laboratories and tutorials. Also, compared to traditional laboratory and tutorial sections, reformed sections appear to allow for more interaction between the nature of lab activities, GTA instructional styles, and student behaviors. This implies that high-quality teaching in reformed laboratories and tutorials may improve student learning experiences substantially, which could then lead to increased learning outcomes. Therefore, effective GTA professional development is particularly critical in reformed instructional environments.



中文翻译：

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在改革后的实验室和教程中表征理科研究生助教的教学实践

背景
研究生助教（GTA）经常领导科学，技术，工程和数学（STEM）的实验室和教程部分，特别是在研究密集型的大型大学中。GTA作为指导者的表现会影响学生的学习经验以及学习成果。在这项研究中，我们在美国东南部的一个研究密集型机构中观察到11个化学GTA和11个物理GTA。我们在一学年中连续两个学期观察了GTA，总共得出58个化学实验室观察结果和72个物理辅导和实验室观察结果。我们使用了根据《大学STEM实验观察协议》（LOPUS）改编的课堂观察协议，以记录GTA和学生的行为。我们将聚类分析分别应用于化学实验室观察以及物理教程和实验室观察相结合。这项研究的目的是在改革的入门实验室和教程中对GTA的教学风格进行分类和表征，探讨GTA的教学风格与学生行为之间的关系，并探讨GTA的教学风格与实验室活动性质之间的关系。

结果
我们确定了化学GTAs中的三种教学风格和物理GTAs中的三种不同教学风格。我们在样本中确定的GTA教学风格的特征与先前在传统的普通化学实验室的研究中确定的特征不同。与同一项先前研究的发现相反，我们发现了GTA的教学风格与学生行为之间的关系：当GTA使用更多的互动式教学风格时，学生会显得更加投入。此外，我们的结果表明实验室活动的性质可能会影响GTA对教学风格和学生行为的使用。此外，我们发现新的GTA似乎比经验丰富的GTA更具交互性。

结论
在改革后的实验室和教程中进行教学时，GTA使用多种教学风格。而且，与传统的实验室和教程部分相比，经过改革的部分似乎可以在实验室活动的性质，GTA教学风格和学生行为之间进行更多的互动。这意味着在经过改革的实验室和教程中进行高质量的教学可以大大改善学生的学习体验，从而可以提高学习效果。因此，在改革后的教学环境中，有效的GTA专业发展尤为关键。