The name comes from the old mechanical tills: 'X' read the totals without clearing them, and 'Z' read them and zeroed them out. The idea survived into modern systems because it does one important job — it draws a hard line at the end of a trading day so the next day starts clean.
A useful Z-Report tells you five things: what you sold, what you gave away in discounts, how the money arrived (cash, card, delivery apps), what was paid out of the drawer for expenses, and whether the physical cash matches the expected figure. That last number is the one worth reading every single day.
A recurring shortage in the same shift, on the same person, is the single clearest early signal of a problem — whether that is a training gap, sloppy change-giving, or something worse. A shop that never checks its Z-Report has no way of noticing the pattern until the amounts are large.
In Outale the Z-Report is produced automatically when a cashier closes their shift. It records the opening float, net sales, discounts, cash rounding, a breakdown by payment method, total expenses paid out, and the difference between expected and counted cash. Closed shifts stay in the audit log with the staff name and timestamp attached, so you can look back at any day.