Measuring and analyzing teaching assistant comfort with content in a reformed introductory physics laboratory course

Across the United States, Introductory Physics Labs are typically broken into multiple sections taught by (often graduate) Teaching Assistants (TAs).At CU Denver, the reformed Introductory Physics Lab TAs are mostly undergraduate physics majors.As part of a larger project studying the transformation and efficacy of these labs, we seek to understand how our TAs prepare, and specifically their comfort with the material.We have designed weekly surveys for our TAs and implemented them over multiple semesters.These surveys probe changes to TA comfort throughout the week: specifically before the preparatory meetings, after the meetings but before teaching, and after teaching.We present a preliminary analysis of these data over one academic year.Results indicate that self-reported TA comfort with the material was high before the weekly meeting and increased or stayed constant afterwards.Changes in comfort following teaching are also discussed, with more mixed results.