While quantitative performance indicators are widely used by organizations and individuals for evaluative purposes, little is known about their impacts on the epistemic processes of academic knowledge production. In this article we bring together three qualitative research projects undertaken in the Netherlands and Austria to contribute to filling this gap. The projects explored the role of performance metrics in the life sciences, and the interactions between institutional and disciplinary cultures of evaluating research in these fields. Our analytic perspective is focused on understanding how researchers themselves give value to research, and in how far these practices are related to performance metrics. The article zooms in on three key moments in research processes to show how "thinking with indicators" is becoming a central aspect of research activities themselves: (1) the planning and conception of research projects, (2) the social organization of research processes, and (3) determining the endpoints of research processes. Our findings demonstrate how the worth of research activities becomes increasingly assessed and defined by their potential to yield high value in quantitative terms. The analysis makes visible how certain norms and values related to performance metrics are stabilized as they become integrated into routine practices of knowledge production. Other norms and criteria for scientific quality, e.g. epistemic originality, long-term scientific progress, societal relevance, and social responsibility, receive less attention or become redefined through their relations to quantitative indicators. We understand this trend to be in tension with policy goals that seek to encourage innovative, societally relevant, and responsible research.