One of the emerging issues facing telephone survey researchers is the proportion of the population residing in ‘mobile phone only’ households.  This population (currently estimated to be around 13% of adults) is not contactable via traditional telephone interviewing methods which only include households with fixed-line telephone connections.  This gap in the coverage of traditional telephone surveys is a problem because it introduces a potential bias into the survey results.  To date, the impact of this under-coverage bias has not been fully explored in the Australian context.

Given the above, the Social Research Centre and the Institute for Social Science Research (ISSR) have conducted what the authors believe to be the first ever Dual-frame telephone survey in Australia.  Two sample frames were used for the survey, a randomly generated list of fixed-line telephone numbers and a randomly generated list of mobile phone numbers.

The objectives of this study were:

• to pioneer the use of a dual-frame survey in Australia
• to better understand the issues involved in conducting telephone surveys using a Dual-frame sampling methodology
• profile the ‘mobile phone only’ population, that is, those persons who live in households without a fixed line telephone connection, and
• to determine the impact that the systematic exclusion of ‘mobile phone only’ persons from traditional fixed-line telephone surveys has on the representativeness of the resultant survey estimates

 As part of addressing these objectives we will explore whether the survey results for the mobile only sample differ from those obtained for the landline sample with respect to a range of socio-economic characteristics and in relation to issues such as:

• general health status
• access to medical services
• tobacco and alcohol consumption
• use of illegal drugs
• experiences of discrimination
• social support networks
• perceptions of safety
• financial hardship, and
• attitudes to contemporary issues such as immigration and the environment.

 The results of this survey have potentially far reaching implications for the practise of survey research in this county.