What does 'impact' mean in the evaluation of learning technology?

Whilst many projects in Higher Education are expected to demonstrate their impact, quite what this requirement means is often left unspecified. This paper draws on the experiences of the EFFECTS project in an attempt to illuminate this issue. The EFFECTS evaluation framework is used to structure this discussion, which explores the complexities associated with identifying impact in terms of student learning, changes in practice for academics, changes within an organisation and national development. Common themes arising from these areas are then identified. Importantly, while practical issues are considered, the purpose of this discussion is not to 'solve' this complexity - instead, its purpose is to recognise it, and to consider the implications for evaluators of working in such settings.