Table 1 Summary of data sources and coding strategies

Class period structure

Categorizing first day structure

Researcher observations of classroom audio/video transcripts

Coded observations for (1) STEM content, (2) course logistics, and (3) all other first day topics at 1-s intervals*

Non-content Instructor Talk

Document the use of non-content Instructor Talk

Researcher observations of classroom audio/video transcripts

Coded observations for presence/absence of nine categories of non-content Instructor Talk at 1 min intervals*

Identify student detection of non-content Instructor Talk

Student responses to survey questions

Analyzed student survey responses about the presence/absence of features associated with non-content Instructor Talk categories within a class period