The ESRC Teaching and Learning Research Programme is the largest ever programme of educational research in the UK. This article reports the purposes, processes, outcomes and issues arising from cross-programme thematic work on the conceptualization of, and research into, 'enhancing learning outcomes' which is a key aim of the programme. Early documentation from thirty projects is analysed, especially in relation to a classification of learning outcomes, dominant metaphors of learning, sector differences and evidence of outcomes. Discussion focuses upon persistent issues concerning the assessment of the broad range of outcomes, what leads to them, and how knowledge of these links might be established.