In this thesis, I use a case study to understand how a realist approach to evaluation (Pawson and Tilley, 1997; Pawson et al. 2004) can contribute to two areas: First Peoples justice programs and parental incarceration. Both areas are highly contextual. First Peoples continue to have adverse experiences with criminal justice systems in Australia. First Peoples are among the most imprisoned populations in the world (Anthony, 2017), with 1,935 per 100,000 (age standardised) Indigenous adults imprisoned in Australia compared to 166 per 100,000 (age standardised) non-Indigenous adults (Productivity Commission, 2021b). Consequently, there are disproportionate rates of Indigenous families with a parent in prison. Parental incarceration has been associated with numerous adverse outcomes for children, parents, family, and community (Arditti, 2012). These impacts stretch across the lifetime as well as intergenerationally and can include negative impacts on mental and physical wellbeing, social marginalisation, anti-social behaviour, and adverse impacts on community wellbeing. These impacts are compounded for over-incarcerated minority groups, including First Peoples. Building an evidence-informed approach to supporting families with a parent in prison is difficult. Families are hard to reach, and the experiences of incarceration are highly variable. This is exacerbated when trying to address the experiences of minority populations. Conducting theory-based evaluations of programs can help improve understanding about the impacts of parental incarceration and how programs can operate to improve outcomes. The realist approach to evaluation is a theory-driven model (Pawson and Tilley, 1997; Pawson et al. 2004). The aim is to seek “what works, for whom, in what respects, to what extent, in what contexts, and how?”. These questions are addressed by identifying generative mechanisms –drivers that promote change in participants. For example, an employment program for people returning home from prison could consider social drivers such as access to opportunities, or psychological drivers such as a person’s job readiness. Realist evaluations also identify the influence of context on how programs work. Context impacts mechanisms as well as a program’s circumstances. For example, for the employment program, opportunities are influenced by location, and job readiness may be influenced by a person’s past workforce experiences. The realist approach recognises that what works in one place may not work in another. Identifying the outcomes, generative mechanisms, and contexts inform why this occurs, and grounds an evidence-informed approach in real-world social environments. In this study I used the realist approach to evaluate Belonging to Family (BtF) - a small-scale reintegration program administered by the non-government organisation SHINE for Kids. BtF has supported First Peoples with a parent in the Mid North Coast Correctional Centre since 2011. With the assistance of SHINE, I focused my evaluation on how and to what extent BtF worked. My research design consisted of two steps. First, I conducted a rapid realist synthesis, an approach systematically reviewing evidence to understand the context, mechanisms, and outcomes of BtF. I synthesised 17 internal documents and 53 external documents to identify BtF’s context, mechanisms, and outcomes. Second, I used the outcomes of the rapid realist synthesis to conduct a realist evaluation. I used an ethnographic approach, based in the field for four months while observing one offering of BtF, from enrolment to completion of their eight-week program. For data analysis I drew upon documents, observational data, and interviews with participants (15 family dyads from eight mothers and seven fathers in prison) and stakeholders (n=5). BtF achieved two primary outcomes (i) strengthening positive family relationships for a parent’s reintegration and (ii) improving participant’s support networks through culturally appropriate services and the community. Due to the highly contextual nature of parental incarceration, mechanisms were triggered dependent on family’s needs. Therefore, the strength of BtF was the highly flexible, person-centric approach. The evaluation also demonstrated how cultural values were an underlying mechanism; cultural values were ingrained throughout BtF and influenced how participants engaged and interacted with the program. In this thesis, I contribute to the literature in five significant ways. First, I demonstrate how a realist approach to evaluation can foreground and embed Indigenous perspectives, methods, and methodologies. Culturally appropriate evaluation methods that embed Indigenous perspectives are crucial for advancing evidence-informed practice; and can significantly contribute to informing criminal justice issues. Second, in terms of the realist method, I demonstrate how a rapid realist synthesis can inform a realist evaluation and provide an opportunity to build rapport with program providers. Third, I demonstrate the importance of understanding how mechanisms work, particularly in areas of service delivery that have disparate participant outcomes. Identifying mechanisms illustrate how a program works, which can assist service providers improve or expand their programs to other sites and strengthen evidence-informed policy and practice. Fourth, I demonstrate that small-scale programs can be an important piece of the puzzle in supporting families experiencing parental incarceration. Many services are needed to address the highly complex and multiple needs of parents in prison and their families and recognising and valuing the role of programs such as BtF is necessary. Finally, I demonstrate how a small-scale program administers a context dependent service delivery. In particularly, I demonstrate how services need to have strong community outreach systems that include a breadth of services, be flexible enough to adapt to the multiple systems within the local context, and respond to the shifting support needs of communities and families. Overall, these five significant findings each inform the existing literature which I explore further in the discussion (Chapter 10). Findings highlight the need for evaluation designs and macro-level policies to be strengthened to support highly contextual service delivery such as programs for parents in prison, particularly for a hyper incarcerated minority population. The findings can also support SHINE in their ongoing improvement of BtF, as well as inform other service providers across Australia and internationally who are developing culturally relevant programs, particularly supporting families experiencing parental incarceration.