These are great questions. The written instrument contains questions that describe situations that LAs may encounter in their interaction with students. LAs need to analyze the information provided and determine how they would provide support. Below is an example (the picture is not presented here):

Students are presented with a picture of three setups a) a single bulb in a circuit with one battery; b) two bulbs in series in a circuit with one battery; and c) two bulbs in parallel in a circuit with one battery. All the bulbs and batteries are identical. They are ranking the brightness of the bulbs.

You approach a group of students and have a conversation with them as shown below:

You: So how would you rank the brightness of the light bulbs?

Students: The bulb in the single circuit is the brightest. The other bulbs are dimmer but equally bright between each other.

You: Why?

Students: Because in the single circuit, there is only bulb that gets all the power from the battery. In both series and parallel circuits, there are two bulbs that share the power from the same battery. Each bulb gets only one half of the power. So the bulbs in b) and c) are half bright as the one in a).

You: Did you calculate the power of each bulb?

Students: Yes, we did. The equation is P=UI. In the single circuit, the power is UI. In the series circuit, I is the same and U is shared by the two bulbs. The voltage of each bulb is U/2. So the power for each bulb is IU/2. In the parallel circuit, U is the same and I is shared by the two bulbs. The current of each bulb is I/2. So the power for each bulb is still IU/2.

Then respondents need to analyze what the strengths and difficulties are in students' understanding and articulate how they would respond to students and why. Their answers can indicate their PCK-Q, i.e., orientation toward questioning, knowledge of curriculum, knowledge of students, and knowledge of appropriate guiding questions. 

This instrument can be used to quantify LAs' PCK-Q and predicate how they intervene with student learning. Once measured, a model can be built about how LAs' PCK-Q contributes to student learning, which will be our focus in the last year of this project. It can also be used for LA preparation and also professional development of high school physics teachers. The participating LAs reported that working on certain questions ahead of time would better prepare them teach the physics concept involved.

As for the last question, I don't have any data yet. This instrument can predict how LAs intervene with student learning, such as using guiding questions to help students overcome a difficulty or directly providing the answer that students need. It's unclear which approach would help with student learning better. Theoretically, it's the former, i.e., guiding through questions. In the last year, we will test that theory by building a model about how LAs' PCK-Q (measured by this instrument) contributes to students' conceptual understanding (measured by conceptual inventory like FCI and BEMA) and critical thinking skills. 

Thanks for the comments. Our major focus is on PCK-Q of learning assistants in non-traditional college physics courses. Learning assistants are undergraduate students who have taken the course and normally received a good grade. They return to the course to facilitate student learning in an inquiry-oriented setting. They are not necessarily pre-service teachers. As for pre-service science teacher education, I have applied this method in my methods course and designed an instrument to measure pre-service teachers' PCK-Q. The questions have a similar format, but are embedded in science concepts at K-8 levels, such as a food chain and light reflection. In my methods course, I have one module (3 weeks) allocated to address guiding questions, especially what guiding questions should be like in order to intervene with students' misconceptions. In Spring 2021, the pre-service teachers took a pre-survey with 10 questions embedded in 10 science topics prior to this module. After this module, they took a post-survey with 10 different questions. Normally, they would demonstrate their skill of questioning in a microteaching with students in the field at the end of this module. Due to COVID, they conducted a rehearsal with peers instead. I am analyzing the data right now. Hopefully, I can share the findings in NARST or AERA next year. Looking forward to your feedback. 

Thanks for your comments and the thought-provoking questions. I completely agree with your comments about the importance of teaching capacities of student assistants, including graduate TA and undergraduate LA. Graduate TAs normally have stronger content knowledge than LAs do. However, they may be equally inexperienced with physics teaching. Their teaching practices may not be as good as those from instructors. It is very challenging to prepare STEM SAs with appropriate teaching capacities. Do SAs need all the pedagogical strategies suggested by educational theories, such as classroom management and scaffolding argumentation? If not, which strategies are most important to them? How should SAs be prepared with those strategies considering that the time for pedagogical instruction is very limited and some SAs even have difficulties with physics content knowledge? We take the first step to answer these questions by identifying questioning as one critical pedagogy for SAs in inquiry-oriented settings. We take the stance of practice-based teacher education (Hiebert & Morris, 2012) and engage SAs in the discussion and reflection of concrete cases with the support of educational theories.

As for your first question, yes, this project involves faculty from college of education (me) and physics department (Dr. Beth Thacker), I am an assistant professor in college of education with a master's degree in physics. My research interest lies in K-8 science education and high school & college physics education. My work involves K-8 science teacher preparation, so I am somehow familiar with the theories about questioning, like Chin's work (Chin, 2007). Q2, so far we have conducted this study in two institutions where SA training happens in the weekly preparation sessions. The preparation sessions are mainly focused on physics content knowledge, i.e., previewing the concepts and activities in the coming week. Right now, we are developing and validating the instrument to probe SAs' PCK-Q. Later on, we will test using this instrument for SA preparation. Q3, we have mentioned STEM education terminology, but not gone deep in the discussion about educational theories. Research and my personal experience suggest that SAs, and even K-8 pre-service teachers do not care about educational theories, or educational theories instructed do not necessarily shape their teaching practice. Q4. We will host a virtual workshop at AAPT this summer on July 10, where we will introduce this instrument. Please join us. Alternatively, you can email me at jianlan.wang@ttu.edu for more details. Looking forward to any possible collaboration.

Thanks for the comments. Yes, questions are of various functions. Learning assistants and pre-service teachers are aware of asking question as a way to hold students accountable to their own learning. However, they are not that knowledgeable about how their questions may intervene with students' conceptual understanding. This is the focus of this project. Looking forward to further discussion.