This report is the second in a series of discussion papers exploring factors that have led New Zealand to have a high incarceration rate. The first report, Using evidence to build a better justice system: The challenge of rising prison costs, covered factors related to incarceration rates and the costs of incarceration. This second report explores factors that are particularly relevant to youth offenders (up to age 25 years).Data for the report were sourced from the Ministry of Justice and the Integrated Data Initiative. The third report - Every 4 minutes: A discussion paper on preventing family violence in New Zealand, will be released in late November. The first drafts were prepared by the Science Advisor to the Justice Sector, Associate Professor Ian Lambie, who has been working with youth offenders and their families for 30 years, assisted by the Chief Science Advisor, Sir Peter Gluckman. Subsequent drafts have incorporated comments and inputs from other departmental science advisors.