What is the difference between occurrences and units?
If you select Occurrences, each attendance code entered on a student's record is counted as one absence. For example, if a student is absent for an entire day and they have 5 classes, the student will have 5 occurrences.
If you select Units, each attendance code is calculated depending on the length of the absence. It will also include tardies if they are included in the attendance calculation.