Cancer Awareness in Hertfordshire, Luton and South Bedfordshire

IntroductionTable 1: Number of returns and confidence interval per survey areaSurvey areaNumber of completedinterviewsConfidence intervalMain sample 1002 +/-3.1%Control area 1 (no letter orleaflet sent)249 +/-6.2%Intervention area (leaflet sent) 507 +/-4.4%Intervention area 2 (letter andleaflet sent)254 +/-6.1%Total 2018 +/-2.2%1.2.2 Questionnaire designThe CAM is a validated questionnaire and as such is standardised to ensureconsistency and comparability of data. However, upon review of the questionnairesome issues were raised by BMG Research with Cancer Research UK, who designedthe validated questionnaire, and minor changes to its design were approved. Thesechanges did not affect any of the questions asked or reduce the data comparabilitywith surveys conducted in other areas.1.3 DataIn total, 2,018 interviews were completed with respondents aged 18+ years. Thesample size of 2,018 is subject to a maximum standard error of ±2.2% at the 95%confidence level on an observed statistic of 50%. Thus, for the quantitative survey, wecan be 95% confident that responses are representative of those that would be givenby the total population of Mount Vernon, if a census had been conducted, to within±2.2% of the percentages reported.This means that if the total population of Mount Vernon had completed the survey anda statistic of 50% was observed, we can be 95% confident that the response liesbetween 47.8% and 52.2%.1.3.1 WeightingTo ensure that the results are representative of the population, the data has beenweighted by PCT, gender, age, and ethnicity to match the 2001 Census data.Weighting is a statistical technique used to counteract the deviations that occur insurvey samples against the population as a whole. In this case, weighting by PCT,age, ethnicity and gender has been used to ensure that the sample used herecorresponds to the overall population of Mount Vernon.At its most basic level, this means that if a national survey of 1,000 people is made upof 550 men and 450 women, then the survey is unrepresentative of the UK populationas 51% is female. Therefore weighting would be applied to give the responses fromfemale respondents slightly more weight (in this case each female respondent wouldbe equivalent to 1.133 people) to give them a representative impact on the finalresults. Conversely, men would be weighted to each count as 0.891 so that theirresponses were not over represented in the final data.5