A short three item pandemic influenza question module was developed as the first part of a larger module of questions on potential threats. These questions were field tested and inserted into the New South Wales Population Health Survey, administered between 22 January and 31 March, 2007 [8] . The New South Wales Population Health Survey is a continuous telephone survey including questions on health behaviours, health status, and access to health services of the state population using the in-house CATI facility of the New South Wales Department of Health [16] . Households were contacted using random digit dialing. Up to 7 calls were made to establish initial contact with a household, and 5 calls were made in order to contact a selected respondent. Only residential phone numbers were used in the sample, as residential phone coverage in Australia still remains high [17] and results from persons who only have mobile phones has been shown to be comparable in the United States [18, 19] . Interviews were conducted in English, Arabic, Chinese, Greek, Italian, or Vietnamese, depending on respondent preference. More details of the sampling approach can be found in the 2007 NSW Health survey report [20] .