American Express scaled its rarest judgment call with software instead of headcount

An authorization decision looked instantaneous from the outside, but a veteran was really weighing a handful of signals — spending pattern, account history, merchant type — learned correctly only after years of seeing how past calls turned out. Hiring ahead of volume meant a pipeline of new authorizers making worse calls than veterans until they caught up, for as long as that catch-up took.

American Express partnered with Inference Corporation to see whether that judgment could be captured directly: interviewing its most experienced authorizers about the exact signals and thresholds behind their calls, rather than assuming the skill could only be transmitted by years on the floor.

The two companies built the Authorizer's Assistant, encoding more than 3,000 core business rules, drawing on up to 13 internal databases of transaction and account history, and deployed it across US Personal and Gold cards in the fourth quarter of 1988 to reproduce the judgment calls that used to require a veteran authorizer.

Encoded 3,000+ rules from veterans into software that pulled account history, so a new hire could make veteran-quality calls on day one.

Authorization decisions are fast lookups across a few signals, not intuition.

Veterans' weighting rules could be elicited and encoded as software logic.

The system pulled from the same databases a human would check.

New authorizers could consult the system and make veteran-quality calls on day one.

When volume outpaces training, capture experts' decision rules into a system juniors can use, decoupling growth from headcount.

The system ran over a decade without rewriting its rule base, maintained by just five people versus the 30–40 typical for a system its size. Authorizer's Assistant became one of the most cited commercial successes of the 1980s expert-systems boom in financial services, credited with letting American Express scale authorization judgment with card volume without scaling headcount at the same rate.