How reconciliation works (the math)
The exact formula NarcCount uses and how the reconciliation window is defined.
The formula
For each drug in a count: Expected = Last Count + Purchased − Dispensed − Destroyed. Variance = Counted − Expected. A variance of zero means your physical count matches the records exactly.
The reconciliation window
“Last Count” is the most recent prior count that included this drug. Purchased, dispensed, and destroyed are summed over the window that runs from the day after that prior count up to and including the current count date.
First count of a drug
When a drug has never been counted before, there is no baseline to reconcile against, so its first count simply establishes the opening balance — no variance is reported. From then on it reconciles normally.
Why expected can differ from a manual tally
Expected is only as accurate as the transaction records behind it. If a purchase, dispense, or destruction is missing or mis-dated, the expected figure will be off — which is exactly the kind of gap a reconciliation is designed to surface.