The importance of demonstrating value for money in terms of academic research beyond the walls of institutions grows stronger as demonstrated by the inclusion of impact assessment in the 2014 REF (Research Excellence Framework) exercise for UK higher education institutions (HEIs). To understand if such focus is influencing the library and information science (LIS) discipline, this paper reports a critical examination of impact case studies submitted to REF 2014 under the Communication, Cultural and Media Studies, Library and Information Management Unit of Assessment. Content analysis was conducted on 25 case studies submitted by 14 institutions, establishing the methodologies, impacts, beneficiaries, published outputs and corroborative evidence reported. The implications of impact assessment on future LIS researcher behaviour, in terms of research conceptualisation and design, were explored through nine qualitative telephone interviews. While individual researchers did not anticipate their behaviour to change due to the introduction of impact assessments, there are anticipated changes across the discipline including a greater focus on engaging with stakeholders and research beneficiaries at early stages of research design and an emphasis on mixed methodologies to maximise the power and consequences of research results.