Powerful Learning Conversations (PLC) sought to improve the feedback that teachers give to pupils in Year 9, by training them to apply techniques used in sports coaching. It is based on the idea that feedback in sports coaching is often provided immediately after a task is performed, and delivered in a way that children are more likely to respond positively to. The training programme adopted a 'cascade' model: expert teachers were trained in the approach and then expected to disseminate their training to English and Maths teachers in their school. PLC was developed in the UK secondary school context by the Youth Sport Trust (YST) in collaboration with the University of Exeter. This feasibility pilot study was conducted in 20 schools between January 2014 and November 2014. It had two aims: (1) to explore whether the programme is feasible and ready for a full-scale trial, and (2) to explore the effect on children's attainment and other outcomes of the programme. Key conclusions include: (1) There was no evidence that the programme had an impact on English attainment; (2) The evaluation detected a positive impact on Maths attainment, but this result is not secure and we are not able to draw firm conclusions about the programme's impact; (3) Interviews and observations with teachers found the programme was implemented in different ways and with different levels of understanding in different schools. This could be avoided by ensuring the programme and its underpinning concepts are more clearly defined; (4) The intervention is not ready to be evaluated using a large-scale trial without further development. In particular, it is important that the programme is more clearly defined and less open to interpretation by teachers; and (5) If the programme is taken to a full trial it is recommended that paper-based tests are used. The pilot provided mixed evidence of promise. There was no evidence that PLC had an impact on English attainment. The evaluation did detect an impact on Maths attainment, which was equivalent to six additional months' progress over the course of a year. However, it is important to note that these results, particularly the Maths result, should be treated with caution. The evaluation did not provide evidence of a differential impact on pupils eligible for free school meals or pupils with a low prior attainment. The evaluation provided mixed evidence regarding the programme's feasibility. The training was well attended by teachers and they appeared to be engaged. Nearly all teachers who took part in the training found it interesting, engaging and relevant to their teaching, and believed that their school as a whole would benefit from the programme. The programme is likely to be affordable if it was delivered at scale.