Contemporary schooling is seen to be altering significantly in light of a combined 'digitisation' and 'datafication' of key processes. This paper examines the nature and conditions of the datafied school by exploring how a relatively prosaic and longstanding school metric (student attendance data) is being produced and used in digital form. Drawing on empirical data taken from in-depth qualitative studies in three contrasting Australian secondary schools, the paper considers 'anticipatory', 'analytical' and 'administrative' aspects of how digitally-mediated attendance data is produced, used and imagined by school staff. Our findings foreground a number of constraints, compromises and inconsistencies that are usually glossed-over in enthusiasms for 'data-driven' education. It is argued that these findings highlight the messy realities of schools' current relationships with digital data, and the broader logics of school datafications.