Mandated work hour restrictions for physicians-in-training began in 2003. The impact of this policy change on patient outcomes and errors remains controversial despite at least one prior study demonstrating fewer errors with shorter shift lengths. This study surveyed New Zealand junior doctors and discovered that night work and unpredictable schedules were associated with greater fatigue measures than total hours worked. The authors used the Australian Medical Association's fatigue risk assessment model and advocate its application as a more comprehensive tool to assess risk for fatigue. These findings support those of a survey study conducted in the United States, which also suggested that error reduction strategies should consider the nature of residents' work rather than simply the number of hours worked.