In this paper we discuss how different observation manuals and coding measures provide information about instructional practices, discursive practices and the content area involved when analysing classroom teaching. While some aspects of classroom practice are likely to be general features that cut across subject areas and grade levels, other features of instruction are almost certainly domain-specific, requiring subject-specific measures. Measures of classroom teaching therefore need to take subject matter into consideration, as instruction interaction and patterns is likely to vary across subjects (Klette et al., 2012; Stodolsky, 1988). The present paper discusses how different coding manuals are able to measure instruction, interaction and subject matter involved, drawing on video analyses from math classrooms and science classrooms in Norway. 9th grade students and their teachers in science (n= 45) and math (n= 38) classrooms from six Norwegian schools are videotaped and analysed. Instructional format and discourse features seem to be adequately measured within the existing coding manuals. Dimensions of the subject matter involved, like for example content activation and cognitive demands, are however hard to measure within an observation format, we will argue, and needs supplementary data or coding lenses in order to provide sufficient information about the subject matter involved.