Offline metrics improved, but the online A/B shows no business lift. How do you explain the gap, and what do you do?
The maturity exam of production ML: a model that's better on paper and worthless in production. Five distinct causes, the funnel diagnostic that separates them, and when the right call is don't ship.
Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
The maturity exam of production ML: a model that's better on paper and worthless in production. Five distinct causes, the funnel diagnostic that separates them, and when the right call is don't ship.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
