We present and describe the development of a framework for assessing or categorizing instructional practices and related conceptions in the context of introductory physics instruction. The purpose of the framework is for articulating practices and conceptions of individual instructors or of curricula. It was developed based on the research literature and interviews with physics faculty and contains ideas with widespread acceptance as well as some outside mainstream rhetoric. We provide an example of how this framework can be applied by using it to categorize aspects of three well-known research-based curricula. The results of this categorization highlight areas that are common in research-based curricular designs and other areas that are less embraced but worthy of consideration.