NRS recognises that the London and South East area is particularly important to many advertisers and publishers.
London and the South East is the most difficult area to interview in – not so much because participants are unwilling to be interviewed, but because they are less often at home.
Apart from the usual measures of making multiple call-backs, and focusing on evenings and weekends, NRS uses an additional special measure to increase the response rate in London:
•Since September 2006 London participants are offered an incentive of £20 in store vouchers for a completed interview. This led to an increase of 10% points in the London response rate, which is now at 40%.
The increase in the response rate in London has also led to an increase in the sample size. Between 2005 and 2012 the total London sample size increased by 45%; the sample size of those of social grade AB increased by 46%, and of those aged 15-24 by 69%.
South East participants have been offered an incentive since 2012 and initial reports have shown an increase of 9% points in the response rate.
