It is a size that enables the reporting of robust data for the UK at a cost that can be borne by the television industry. The substantial cost of increasing the size of the panel would not be reflected in tangible benefits, unless the increase were to be radical, something like a four-fold increase, the cost of which would be truly prohibitive. The sample of panel homes is distributed according to each area’s proportional population size, except in regions where this would result in samples considered too small to adequately serve a region. The samples in Scotland, Wales, Northern Ireland, Border, South West and West of England are “boosted” to achieve a meaningful number of homes. There are around 11,500 people in the 5,100 panel homes and each home and individual in the sample represents, on average, roughly 5,000 of the UK population.
The BARB panel is designed to allow for continual change. At any given time there are many more than 5,100 UK homes installed with BARB television meters in order to ensure the daily reporting sample is at least 5,100 homes. The average annual rate of panel churn is about 20%, which is low compared to previous BARB panels. Panel members may ask to leave the panel at any time. Alternatively homes may be removed from the panel by BARB to be replaced by other homes, in order to maintain the balance of the panel.
In addition to the size of the sample, quality is an important consideration. The methods used to build the panel are based on the highest standards of research practice, using probability sampling to ensure it remains representative of the UK as a whole. Panel homes are located across the UK and the viewing of all individuals aged 4 years and over within the household, plus their guests, is collected on a daily basis.