The increasingly complex nature of contemporary social problems and the search for tailored and appropriate responses requires the development of sophisticated methods of inquiry. Data linkage as a method has to date seen limited application beyond health research. However, there has been a growing recognition within the human service and criminal justice sectors of the need to utilize client and intervention data more effectively to explore and understand the broader social context of their clients’ lives. This paper reports on a methodology using data linkage developed by researchers at the University of New South Wales to examine pathways through health, human service and criminal justice agencies for a cohort of people with mental health and cognitive disabilities who have been in prison. The methodology brings together data from ten agencies across the health, human service and criminal justice sectors in NSW to simultaneously take account of the linear, multilayered and multiagency experiences of vulnerable individuals. The picture that emerges has the potential to identify and inform more appropriate, responsive and cost effective service models that can take account of the complex needs of this group.

This paper offers insights from the research focused in two key areas – the compilation of the dataset and the new insights that achieving such linkage enables.  In compiling the dataset issues discussed include: sourcing appropriate data, awareness of the range of purposes for which data is collected, and variation in collection over time. In particular the paper will explore the complex challenges associated with identification and matching of individuals across systems, as this is particularly problematic when researching within and beyond the criminal justice system where the use of aliases and the mobility of the population is marked.  The paper concludes by offering a range of examples from the study to illustrate the types of insights that are made possible through multi-sector interagency data linkage research, and the ways that these can be applied to build capacity to understand complex populations and enhance evidence-based policy and practice in the field.