Field notes › Rostering
Rostering day and night shifts without double-ups
A double-up is a booking a worker cannot possibly honour. Rostered on days and nights at the same site. Booked on nights at one site and days at another on the same date. Told to start at 6am when their night shift finishes at 6am. Every coordinator running mixed day and night rosters has shipped at least one of these, and it is almost never carelessness. It is the tooling.
Night shifts break spreadsheets
A day shift fits neatly inside one calendar date. A night shift does not. It starts Tuesday evening and finishes Wednesday morning, but a spreadsheet records it in one cell, usually Tuesday's. On paper, Wednesday looks free. Book that worker onto Wednesday's day shift and you have created a physically impossible roster that passes every visual check you can throw at it.
The person who built the spreadsheet usually knows the convention and reads around it without thinking. The person covering their annual leave does not, which is why these mistakes cluster around handovers, holidays and anyone new to the roster.
Where double-ups actually come from
Watch a season of mixed rosters and the same sources keep turning up.
- Separate rosters per site. The clash exists across two files, so neither file shows it. The worker is the only person who can see their whole week.
- Panel rotation. Crews swapping from a day block to a night block inside a swing, where the turnaround day is easy to get wrong by exactly one row.
- Rushed cover. A gap gets filled at 5.30am by whoever answers the phone, and nobody checks what else that person is already booked on.
- Stale availability. The worker told someone weeks ago they were away that Wednesday, and the note never made it out of a text thread.
Rotating crews between days and nights
Plenty of sites rotate crews between day and night blocks rather than running a dedicated night crew, and the rotation itself is fine. The risk concentrates in the turnaround, the gap between the last night shift and the first day shift, because that is where fatigue and rostering errors pile up together. A roster that shows dates but not start and end times will happily let you schedule a turnaround that no fatigue plan would sign off on.
Keep turnarounds inside whatever your client's fatigue management plan requires, and be wary of borrowing rules from another site, because fatigue guidance differs by state and by industry. If you are not sure what applies to your crew, check with your state regulator rather than guessing.
Make double-ups impossible to book
Discipline gets you part of the way. One master roster instead of a file per site. Real start and end times recorded for every shift. A standing rule that nobody books cover without checking the worker's whole week. But every manual system still relies on a human noticing the clash, and humans miss things at 5.30am with a client on hold.
Mustr takes the noticing out of it. A night shift is stored with its real start and finish times, not as a mark in a date cell, and every booking is checked server-side against the worker's existing shifts before it lands. A clash blocks the booking outright. Not a warning, a hard stop. Because there is one roster timeline across every client site, days and nights together, the check sees bookings the coordinator has forgotten about and files they have never opened. Availability from the worker portal is checked in the same moment, so a shift cannot land on a day the worker marked as unavailable.
That changes where errors get caught. Instead of a double-up surfacing at the gate, or worse, in a conversation with your client, it dies quietly at booking time as a blocked action, and the coordinator picks someone who can actually work the shift.
If your night shifts live in date cells and your double-ups get caught at the gate, see it on your own roster.