A randomized questionnaire-based study on the impact of providing numerical information on colorectal cancer screening

OBJECTIVES To establish whether the provision of numerical data using pictograms and framed as event rates affects subjects' attitudes to colorectal cancer (CRC) screening. DESIGN Randomized questionnaire and telephone study comparing a control group given standard NHS CRC information leaflets with an intervention group given the same leaflet but enhanced with additional numerical and pictorial information. SETTING District General hospital and two general practices in North East England. Study carried out immediately prior to the introduction of CRC screening. PARTICIPANTS A total of 478 non-gastroenterological subjects (age range 60-70 years). MAIN OUTCOME MEASURES The difference in the two groups' overall wish to be screened; comparison of the impact of enhanced vs. unenhanced summary points in the NHS information leaflet; the summary point that most influenced their decision on screening; the views of the intervention group on the additional numerical and pictorial information provided. RESULTS A total of 256 (54%) responded (124 from the control group and 117 from the intervention group); 22% were interviewed by telephone; 90% of the control group and 85% of the intervention group wished to be screened (P = 0.34). Provision of numerical and pictorial information significantly changed the impact of five of the six summary points on the decision to be screened. Sixty-two percent of the intervention group found the pictograms helpful while 83% of those interviewed by telephone found the numerical data helpful; 73% of the control group when given by telephone the additional numerical information given to the intervention group said this would have been useful in aiding their decision-making. CONCLUSION Providing additional numerical information would enhance the credibility of the screening programme without necessarily reducing the numbers screened.