A common procedure among researchers studying sentencing is to identify statistical variation and explain this through interviewing practitioners about policies and procedures. This paper reports findings from a study that seeks to explain differences in detention rates between children’s courts in three Australian states (Tasmania, Victoria and New South Wales), primarily through observing sentencing hearings. It starts by considering whether the lower rate in Victoria indicates that magistrates are more lenient or, alternatively, that young people commit fewer offences in this state. The paper demonstrates, through comparing cases with similar features, that Victoria is more tolerant. There may also, however, be significant differences within states, both between metropolitan and country courts, and individual practitioners. Case by case comparison using qualitative methods can strengthen quantitative data, even though a stronger scientific explanation requires investigating decision-making processes within court cultures using ethnographic methods.