This article considers arguments for and against the use of coding systems in classroom-based language research and touches on some relevant considerations from ethnographic and conversational analysis approaches. The four authors each explain and elaborate on their practical decision to code or not to code events or utterances at a specific point in a specific research project. Three of the researchers have chosen mixed research designs, of which two involve some coding at the data collection stage, the third only as part of later analysis. The fourth researcher concentrates on the data collection stage and offers a five-part rationale for not coding at this stage. (Contains 51 references.) (Author/MSE)