An RDO, rostered day off, is an Australian and New Zealand arrangement where slightly longer daily hours accrue into a scheduled paid day off, commonly one per four-week cycle. It is standard in construction and manufacturing and common enough in offices to shape attendance patterns.
For workplace planning, RDOs are a predictable attendance signal: teams with cycled RDOs have known light days. Feeding them into the attendance picture keeps desk forecasts honest, especially in Australian offices where the pattern is widespread.