Metrics evoke a mixed reaction from the research community. A commitment to using data and evidence to inform decisions makes many of us sympathetic, even enthusiastic, about the prospect of granular, real-time analysis of our own activities. If we as a sector can't take full advantage of the possibilities of big data, then who can? Yet we only have to look around us, at the blunt use of metrics such as journal impact factors, h-indices and grant income targets to be reminded of the pitfalls. Some of the most precious qualities of academic culture resist simple quantification, and individual indicators can struggle to do justice to the richness and plurality of our research. Too often, poorly designed evaluation criteria are "dominating minds, distorting behaviour and determining careers." 1 At their worst, metrics can contribute to what Rowan Williams, the former Archbishop of Canterbury, calls a "new barbarity" in our universities. 2 The tragic case of Stefan Grimm, whose suicide in September 2014 led Imperial College to launch a review of its use of performance metrics, is a jolting reminder that what's at stake in these debates is more than just the design of effective management systems. 3 Metrics hold real power: they are constitutive of values, identities and livelihoods. How to exercise that power to positive ends is the focus of this report. Based on fifteen months of evidence-gathering, analysis and consultation, we propose here a framework for responsible metrics, and make a series of targeted recommendations. Together these are designed to ensure that indicators and underlying data infrastructure develop in ways that support the diverse qualities and impacts of UK research. Looking to the future, we show how responsible metrics can be applied in research management, by funders, and in the next cycle of the Research Excellence Framework. The metric tide is certainly rising. Unlike King Canute, we have the agency and opportunityand in this report, a serious body of evidenceto influence how it washes through higher education and research. Let me end on a note of personal thanks to my steering group colleagues, to the team at HEFCE, and to all those across the community who have contributed to our deliberations.