As part of a larger evaluation of the YCS,15 eight questions,
three of which were contingent on the responses to other questions,
were added to a national omnibus survey, which was carried
out by the British Market Research Bureau (BMRB) (http://
www.tns-ri.co.uk/what-we-do/bmrb-omnibus.aspx) by telephone
over two weekends in January 2009. A UK database of
residential numbers is the source of the master sample used by
BMRB for its telephone omnibus service. New numbers are
created by adding or subtracting up to 40 from each original
number. Duplicated numbers are removed from the listing. Samples
for each omnibus survey are selected from the master sample
using random-digit dialling and a constant sampling
interval. This method ensures that numbers not listed in telephone
directories can still be included in the sample. Each residential
number has an equal chance of being dialled. Any adult
aged 16 or above living in the household is eligible for interview.
To ensure that the final sample does not over-represent the
groups that spend more of their time at home, criteria known to
relate to an individual’s likelihood of being at home are used to
control selection from the eligible adults. If a ‘no reply’ is
obtained at the first calling or if the respondent requests an
appointment at a different time, the household is recalled.
Questions were developed to assess public knowledge of the
YCS and their preferences for methods of reporting ADRs. In
addition, we asked about respondents’ previous experiences of
side effects from medications and whether they had ever
reported these.