In Schedules, if part of the schedule is overstaffed and is red in the Coverage panel, the red shading reflects how overstaffed the schedule is at that time. The same goes for understaffing; the shade of yellow indicates how understaffed the schedule is.
Additionally, the color’s location in each cell indicates at what time of day the schedule is over- or understaffed. For example, the left-most side of each cell represents the morning hours, the middle of each cell represents the middle of the day, and the right-most side of each cell represents the afternoon and evening hours.
The following screenshot shows an example of the Cashier activity in Coverage panel with various shades of yellow, green, and red:
In the above example, the Cashier activity has mostly good coverage on Monday, indicated by all of the green in the cell:
Tuesday, however, has a lot of over and understaffing, evident in its cell by the red shades in the beginning and middle of the day and the yellow at the end of the day:
The darker the color, the more understaffed or overstaffed the activity is for that time of day. For example, early on Tuesday, the dark red sliver indicates a lot over overstaffing for that period:
Later in the day, the slivers of yellow indicate very mild understaffing during those periods:
Earlier in the day is a variety of moderate over- and understaffing, indicated by the various lighter shades of red and yellow:
Clicking any of these periods opens that period in the week’s schedule under the Coverage panel, so that you can examine the specific staffing issues.