The "+1" and "-1" notations in the on-call schedule are used to indicate overnight shifts that spans across two days.
"+1" signifies that the shift extends into the next day. For example, a shift listed as "19:00 - 06:00 (+1)" means it starts at 7:00 PM on the current day and ends at 6:00 AM the following day.
"-1" indicates that the shift started on the previous day and ends on the current day. For instance, "19:00 (-1) - 06:00" would mean the shift began at 7:00 PM the previous day and ends at 6:00 AM on the current day.
When viewing the on-call schedule for previous days or future days, the shifts will show up with the relation to current date.
For example:
In this image, Nov 28th is the current date. When viewing Nov 29th's schedule (in the future), Olivia Low's shift is listed as "19:00 (-1) - 06:00", which means her shift started on November 28th at 19:00 PM and ended on November 29th at 6:00 AM.
Umar Azhar's shift is listed as "19:00 - 06:00 (+1)", meaning his shift starts on November 29th at 19:00 PM and will end on November 30th at 6:00 AM.
You can view your on-call schedule on "My Schedule" tab for a clearer view, or import to your personal calendar platform if you prefer another view.