Research into classroom dialogue suggests that certain forms are especially productive for students' learning. Despite the large number of studies in this area, there is inadequate evidence about the prevalence of the identified forms, let alone their productivity. However, scarcity is widely presumed. The overall aim of the study reported in this article was to examine the extent to which the forms are embedded within current practice in English primary schools. Video-recordings of two lessons from each of 36 classrooms formed the database, with two subjects from mathematics, English and science covered in each classroom. Each lesson was coded per turn for the presence of 'dialogic moves' and rated overall for the level of student involvement in specified activities. Results revealed that the supposedly productive forms were not always as scarce as sometimes presumed, while also highlighting huge variation in their relative occurrence. They also point to the role of professional development (PD) for teachers in promoting use of some forms.