Non-response bias in a lifestyle survey

Monitoring health targets is often undertaken using questionnaire surveys of lifestyle risk factors. Non-response bias is recognized but rarely quantified.

Following a questionnaire survey on a random sample of 6009 residents of Somerset with a response rate of 57.6 per cent, a telephone survey was undertaken on a random sample of 400 non-responders. A small number of the more important questions from the questionnaire were put to the non-responders over the phone.

Fifty-nine per cent of the sample were contacted and agreed to participate. Statistically significant differences between responders and non-responders to the original questionnaire were detected for current smoking, hazardous alcohol consumption and lack of moderate or vigorous activity.

Lifestyle questionnaire surveys need to include an assessment of the non-response bias.