In early 2001, Australia experienced a sudden and dramatic decrease in heroin availability, concomitant with increases in price and decreases in purity. This phenomenon, known as the 'heroin shortage', was assessed in a comprehensive body of research examining the causes, course and consequence of the shortage. As a result of those findings a number of additional questions were raised, and some findings required further and more detailed analysis, which are addressed in the current report. The aims of the research presented in this report were to: i) assess what impact, if any, the heroin shortage had on initiation to heroin use; ii) examine whether the associated increase in cocaine use led to an increase in violent crime and an increase in sex work; iii) provide a more detailed and analytical analysis of fatal and non-fatal drug overdose; and iv) provide a closer examination of the impact of law enforcement operations on harm reduction in the context of the heroin shortage. (Executive summary, edited)