A change in the Barb universe estimates by ethnic group 22 May 2018 The TV household population, which is referred to as the universe, forms the basis for the audience estimates published by Barb. Our universe estimates are derived from two main sources: Estimates for the total UK population are derived from Office for National Statistics (ONS) data. Barb receives these from JICPOPS, a joint industry body that supplies universe estimates for all media research currencies. Barb’s Establishment Survey provides estimates for the proportion of households with TV sets. The Establishment Survey is weighted to JICPOPS population estimates, to ensure it accurately reflects the age, sex, regional and household size profile of the UK’s population. Universe estimates are updated each month and change regularly as a result of fluctuations in overall population levels. We have recently made a change to Establishment Survey weighting which affects how we calculate universes, in order to give more up-to-date estimates of the population of ethnic groups. The Establishment Survey will be weighted to population estimates for ethnic groups, based on ONS data. The revised universes resulting from this will be used in the calculation of viewing data from 1 June 2018. In preparation for the change, we assessed the new methodology on our February 2018 data, comparing the newly-calculated universes with the existing published ones. The assessment indicated that a number of minority ethnic groups are likely to see small increases in universes following this change. In turn, these newly-calculated ethnic group universes are likely to lead to an increase in reported viewing levels for channels predominantly targeted to ethnic groups. The assessment also indicated a marginal decline in total TV viewing of 0.2%, likely due to lower viewing levels by individuals in the new, larger minority ethnic group universes.