A debit authorization either gets approved or it doesn't. Add those up over a month and you have an approval rate.
It's one of the few card-program numbers that comes straight out of a report most banks already receive — the authorization summary.
The level on its own doesn't tell you much. A bank running a conservative fraud posture and a bank running a looser one can both be working exactly as intended.
The direction is what's worth watching. If that share moved year over year, something changed — a rule, a model, a vendor setting, a shift in where cardholders are spending. The number moving is the signal. Finding out what moved it is the work.
This week's board question:
"What share of our debit authorizations do we approve — and has that changed?"
One note before anyone runs it: take insufficient-funds declines out first, or the number won't mean what you think it means.
Watching that number over time, and finding what moved it, is what PDEX does.