Enhancing national data to align with policy objectives: Aboriginal and Torres Strait Islander smoking prevalence at finer geographic levels.

Objectives The aim of the study was to assess the utility of national Aboriginal survey data in a regional geospatial analysis of daily smoking prevalence for Aboriginal and Torres Strait Islander Australians and discuss the appropriateness of this analysis for policy and program impact assessment. Methods Data from the last two Australian Bureau of Statistics (ABS) national surveys of Aboriginal and Torres Strait Islander people, the National Aboriginal and Torres Strait Islander Social Survey 2014-15 (n=7022 adults) and the National Aboriginal and Torres Strait Islander Health Survey 2012-13 (n=10896 adults), were used to map the prevalence of smoking by Indigenous regions. Results Daily smoking prevalence in 2014-15 at Indigenous regions ranges from 27.1% (95%CI 18.9-35.3) in the Toowoomba region in Queensland to 68.0% (95%CI 58.1-77.9) in the Katherine region in the Northern Territory. The confidence intervals are wide and there is no significant difference in daily smoking prevalence between the two time periods for any region. Conclusion There are significant limitations with analysing national survey data at finer geographical scales. Given the national program for Indigenous tobacco control is a regional model, evaluation requires finer geographical analysis of smoking prevalence to inform public health progress, policy and program effects. Options to improve the data currently collected include increasing national survey sample sizes, implementing a smoking status question in census surveys, investing in current cohort studies focused on this population or implementing localised surveys. What is known about the topic? The last geospatial analysis of Aboriginal and Torres Strait Islander smoking prevalence was undertaken in 1997. Current national survey data have not been analysed geospatially. What does this paper add? This paper provides new insights into the use of national survey data for understanding regional patterns and prevalence levels of smoking in Aboriginal and Torres Strait Islander populations. What are the implications for practitioners? The findings of the study suggest caution when interpreting prevalence maps and highlight the need for greater sample sizes in national survey data. The analysis is also an opportunity to assess the use of national survey data in evaluating the policy impact of programs targeted at a regional level.