NRS calibrates its estimates for PC and Mobile audiences to match estimates published by comScore, as the chosen supplier to UKOM.
Previously this was done by matching to comScore’s estimates in terms of % penetration of the digital universe. However, due to some differences in how the comScore and NRS universes are defined, that led to a corresponding difference in the overall number of gross visitors per platform between the two datasets.
With effect from the release of NRS PADD in June 2015 (April 2014 – March 2015/comScore March 2015), comScore’s absolute estimates by platform (rather than % penetration) will be set as the target for the calibration process. This will resolve the differences previously observed.
