Summary
In 2000, New South Wales implemented legislation that permits police to take a DNA sample from any offender serving a sentence for a serious indictable offence. This report examines the impact of this legislation on clear-up prosecution and conviction rates. For conviction rates, the study found no evidence that the advent of DNA testing had a positive impact. For the police outcome series of clear-up, charge, and charge to clear-up rates, there was consistent evidence of a positive association for five of the eight crime categories considered and mixed evidence for the assault and the two motor vehicle related categories. For the police outcome series, the lags at which the association with the advent of DNA testing and subsequent database growth was quite long and varied across crime categories. From shortest lag to longest lag, the lags included break and enter non-dwelling, sexual assault, break and enter dwelling, robbery without firearm, and robbery with firearm. The differences in lags across categories could be attributed to differences in average prison sentences for these crimes.
Contents
1. Introduction -- 2. Past research -- 3. The present study -- 4. Issues in identifying suitable control series or covariates series -- 5. Statistical models and methods -- 6. Analysis of police data on clear up and charges laid rates --7. Analysis of convictions in local and higher courts -- 8. Summary of results and assessment of impact of advent of DNA testing -- 9. Discussion -- 10. Further research -- 11. References -- 12. Notes.