Interactive decision making (IDM) refers to teachers' selection and rejection of alternative courses of action during instruction. Previous research indicates that teachers report making interactive decisions when their plans are disrupted. A study generated hypotheses about teachers' IDM using the grounded theory approach--an inductive system for generating interrelated hypotheses grounded in the empirical. Twelve elementary school teachers conducted lessons in their classrooms and recorded them on audiotape. Within 48 hours of the lesson, these teachers were interviewed using the stimulated-recall technique. These interviews were audiotaped and transcribed. Ideational units were compared and contrasted, categories were constructed--all followed by numerous returns to the data where categories and then hypotheses were revised using the constant comparative technique. Three hypotheses were generated: (1) Teachers' IDM is embedded in classroom learning activities; (2) Teachers' intentions during interactive teaching are to move learning activities forward to completion; and (3) This intention is supported by IDM routines. A concluding discussion points to learning activities as mediators of the structural tension between unlimited subject matter and limited time. Implications for the implementation of curricular innovations are suggested. (Author/JD)