Measures of the gap in living standards, life expectancy, education, health and employment between Indigenous and non-Indigenous Australians are primarily derived from administrative data sources. However, Indigenous identification in these data sources is affected by administrative practices, missing data, inconsistency, and error. As these factors have changed over time, assessing whether the gap between Indigenous and non-Indigenous Australians has changed over time, based on data unadjusted for these sources of error can potentially lead to misguided conclusions. Combining administrative data on the same individuals collected from different sources provides a method by which a more consistent derived Indigenous status can be applied across all records for an individual within a linked data environment. We used the Western Australian Data Linkage system to produce derived Indigenous statuses for individuals using a range of algorithms. We found that these algorithms reduced the amount of missing data and improved within-individual consistency. Based on these findings, we recommend our Multi-Stage Median algorithm be used as the standard indicator of Indigenous status for any reporting based on administrative datasets when multiple datasets are available for linkage, and that algorithmic approaches also be considered for improving the quality of other demographic variables from administrative data sources.

IntroductionMainstream Australian mental health services are failing Aboriginal young people. Despite investing resources, improvements in well-being have not materialised. Culturally and age appropriate ways of working are needed to improve service access and responsiveness. This Aboriginal-led study brings Aboriginal Elders, young people and youth mental health service staff together to build relationships to co-design service models and evaluation tools. Currently, three Western Australian youth mental health services in the Perth metropolitan area and two regional services are working with local Elders and young people to improve their capacity for culturally and age appropriate services. Further Western Australian sites will be engaged as part of research translation.Methods and analysisRelationships ground the study, which utilises Indigenous methodologies and participatory action research. This involves Elders, young people and service staff as co-researchers and the application of a decolonising, strengths-based framework to create the conditions for engagement. It foregrounds experiential learning and Aboriginal ways of working to establish relationships and deepen non-Aboriginal co-researchers’ knowledge and understanding of local, place-based cultural practices. Once relationships are developed, co-design workshops occur at each site directed by local Elders and young people. Co-designed evaluation tools will assess any changes to community perceptions of youth mental health services and the enablers and barriers to service engagement.Ethics and disseminationThe study has approval from the Kimberley Aboriginal Health Planning Forum Kimberley Research Subcommittee, the Western Australian Aboriginal Health Ethics Committee, and the Curtin University Human Research Ethics Committee. Transferability of the outcomes across the youth mental health sector will be directed by the co-researchers and is supported through Aboriginal and non-Aboriginal organisations including youth mental health services, peak mental health bodies and consumer groups. Community reports and events, peer-reviewed journal articles, conference presentations and social and mainstream media will aid dissemination.

Our findings suggest that mainstream antismoking mass media campaigns can positively influence the thoughts and behaviours that Aboriginal smokers have, and exhibit, towards quitting smoking. Notwithstanding this, advertisers should continue to look for better ways to incorporate Aboriginal themes in campaign messages. Future mainstream antismoking campaigns should source sufficient funds to ensure that advertising messages reach the large Aboriginal populations in regional and remote Australia.

Prof Forbes conceptualized and designed the study, was responsible for obtaining funding, reviewed and revised the manuscript, and critically reviewed the manuscript for important intellectual content regarding aspects of gastroenterology. Dr Ravikumara conceptualized and designed the study, was responsible for obtaining funding, reviewed and revised the manuscript, and critically reviewed the manuscript for important intellectual content regarding aspects of gastroenterology. A/Prof Jacoby conceptualized and designed the study, was responsible for obtaining funding, provided specialist statistical support, and reviewed and revised the manuscript. Ms Bourke collected data for the study, and critically reviewed the manuscript for important intellectual content regarding aspects of intellectual disability. Dr Srasuebkul reviewed and critically reviewed the manuscript for important intellectual content regarding aspects of intellectual disability. Prof Trollor conceptualized and designed the study, was responsible for obtaining funding, reviewed and revised the manuscript, and critically reviewed the manuscript for important intellectual content regarding aspects of intellectual disability. Dr Wilson conceptualized and designed the study, was responsible for obtaining funding, reviewed and revised the manuscript, and critically reviewed the manuscript for important intellectual content regarding aspects of pediatric medicine. Prof Nagarajan conceptualized and designed the study, was responsible for obtaining funding, reviewed and revised the manuscript, and critically reviewed the manuscript for important intellectual content regarding aspects of pediatric medicine. A/Prof Jenny Downs conceptualized and designed the study, was responsible for obtaining funding coordinated and supervised linked data collection, reviewed and revised the manuscript and was the principal investigator of the research. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.