This chapter has a focus upon the evaluation ways of working within the Mayor’s Office for Policing and Crime. Stressing the role of evaluations within democratic accountability and oversight and how the evaluation function evolved over a period of ten years. A journey that began with individual evaluation requests and was able to develop as a centre of excellence via issues of pragmatism, proportionality, and close internal working with policy. The latter stages are characterised through the attempt to stretch the underpinning logic of evaluations and standardised outcomes across the organisation to promote wider system-wide evidence-based decision-making.