Occurrence Points Attendance Tracker - rolling year

SUM works well across multiple sheets, but SUMIFS is trickier. A solution could be forced using INDIRECT, but the easiest approach might be to simply use helper columns. You can create a column (D) on each year's sheet for Unscheduled Absences in the last calendar year. You could then use the following formula in D6 to get that total:

=COUNTIFS($K6:$NK6, "UA",$K$5:$NK$5,">"&TODAY()-365)

On your Rolling Occurrences sheet, just change C6 to:

=SUM('2016:2018'!D6)

Repeat for late arrivals and early leave. This approaches uses a few extra columns, but it's rather intuitive and should be easy to adjust and adapt, if necessary. In the attachment, I made the aforementioned changes for UAs only, so you can see how it looks. You'll also need to change your dates for each year. The cell says "1/1", but it actually stores "1/1/2013". You'll need to change the 2013 to the appropriate year. Take a look at the attachment and see if it'll work for you: