Promoting Alternative Thinking Strategies (PATHS) is a school-based social and emotional learning (SEL) curriculum that aims to help children in primary school manage their behaviour, understand their emotions, and work well with others. PATHS consists of a series of lessons that cover topics such as identifying and labelling feelings, controlling impulses, reducing stress, and understanding other people's perspectives. It is delivered twice weekly in 30-40 minute lessons by teachers to all children in a given class, typically in the slots allocated for Personal, Social and Health Education. This curriculum is supplemented by activities that support the application of new skills during the school day and activities that are sent home to parents that cover the topics taught in class. In this trial, 45 participating schools from Greater Manchester were randomly allocated to implement PATHS for two years (school years 2012-2013 and 2013-2014) or continue their usual practice during the same period. This evaluation focuses on the academic outcomes of the intervention for children in Years 5 and 6 in English/reading and maths. The outcomes of this study include: social and emotional competence, quality of life, and attendance. Key conclusions are as follows: (1) Overall, PATHS did not have a positive impact upon children's academic attainment; (2) The evidence does not indicate that PATHS produced differential gains for children eligible for free school meals (FSM); (3) Higher levels of PATHS implementation quality and reach were associated with better academic outcomes; (4) Teachers reported a lack of time to implement PATHS at the recommended frequency. On average, only half of the lessons were delivered; and (5) While PATHS does not appear to be a cost-effective way of improving students' attainment, it may have an impact on other, non-cognitive outcomes. A full report on the NIHR trial looking at these outcomes will be published at a later date. Overall, the findings of this study can be considered to be robust and secure. Additionally, it is worthy of note that the study also complied with the EEF's various quality markers.