In a recent briefing paper on breaks and discontinuities in official data series in the UK, two of us [Dixon and Hood] highlighted the tension between the demand for quantitative evidence to drive performance improvement and the tendency to systematically destroy the very evidence by which performance can be evaluated. This paper was discussed, and further examples of data breaks across the public sector were explored, at a seminar at LSE in April, attended by senior civil servants and academics. The ensuing discussion embodied the same tensions, with some participants emphasising the need for indicator continuity, and others stressing that indicators must change as methodologies, purposes, and audiences evolve. Can this tension be resolved? In this article we suggest that recommendations arising from the seminar might point to a way to reconcile these demands.