Jamieson, LisaSmithers, LisaRoberts, RachelRibeiro Santiago, Pedro Henrique2020-04-272020-04-272020http://hdl.handle.net/2440/124410Background: The history of colonization contributed to Aboriginal and Torres Strait Islanders becoming one of the most disadvantaged groups in Australia. The experienced inequalities in virtually all areas, including employment, income and educational attainment, generate chronic stress, low sense of personal control and lack of social support in the Aboriginal population. Despite these psychosocial variables (perceived stress, sense of personal control and social support) being suggested as important to Aboriginal health, the only measurement instruments available were originally developed in Western countries, with no instruments validated specifically for Aboriginal Australians. The aim of this PhD project was to evaluate the validity and reliability of the Perceived Stress Scale (PSS-14), Social Support Scale (SSS) and Sense of Personal Control Scale (SPCS) in an Aboriginal population. Methods: The main sample was composed of 367 pregnant Aboriginal women who participated in the Baby Teeth Talk Study, an oral-health randomized controlled trial (RCT) conducted in South Australia. Secondary samples comprised: (1) 317 Aboriginal participants from the Teeth Talk Study, an RCT designed to improve oral-health literacy; and (2) 3,857 non-Aboriginal Australians in the population-based cross-sectional study Australia’s National Survey of Adult Oral Health 2004-2006. The psychometric properties of the three scales were analyzed with the Rasch model and Graphical Log-linear Rasch models. The properties evaluated were: (a) dimensionality, (b) model fit, (c) item fit, (d) local dependence, (e) differential item functioning (DIF), (f) reliability, (g) targeting and (h) criterion validity. Conclusions: The findings indicated initial evidence of validity from a revised PSS, after the exclusion of one misfitting item, and a revised SPCS, after the exclusion of five misfitting items. In the case of the SPCS, the development of new culturally specific items is recommended. There was robust evidence that the original 4-item version of the SSS is valid for Aboriginal Australians considering that the good psychometric properties were replicated in two independent samples. The overall conclusion was that, while certain instruments required more modifications than others (e.g. SPCS compared to the SSS), adapted versions of the 3 instruments are available for future research with Aboriginal Australians.enAboriginal AustraliansValidation studiesItem-response theoryRasch analysisDifferential item functioningThesis