Detecting recommissioning

Method of detecting a change in a lighting system comprising a plurality of devices each comprising a luminaire and/or a sensor, wherein each respective one of the devices has a respective location recorded in a commissioning database in association with data reported by the respective device; the method comprising: identifying a subset of said devices located within a predetermined spatial demarcation; automatically monitoring a respective value of a characteristic of each of the devices in said subset, thereby forming a data cluster comprising the values of said characteristic for the subset; automatically detecting that one of one of the devices in the subset has been moved by detecting a shift in one of the cluster values relative to the rest of the values in the data cluster; and in response to said detection, automatically outputting an indication that the commissioning database is likely to require updating to reflect said change.