Assessment for Learning (AfL) is an established learning and teaching strategy. The authors identify issues with the effectiveness of its application in the classroom. Having noted a theoretical shift from teacher-generated to pupil-generated success criteria, the authors were keen to explore how this could be realised in practice. They developed a model based on AfL principles, which they introduced to a class of Year 5 pupils. They found that, whilst pupils can identify their own success criteria, a number of issues need to be considered by the innovative teacher. (Contains 2 tables and 4 figures.)