Model a dimension bitemporally so you can answer 'what did we believe the customer's plan was, as of last Tuesday?'
SCD2 tracks when an attribute was true; bitemporal also tracks when you knew it. The question separates engineers who can audit a number from those who quietly overwrite history when a correction arrives.
Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
SCD2 tracks when an attribute was true; bitemporal also tracks when you knew it. The question separates engineers who can audit a number from those who quietly overwrite history when a correction arrives.
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.
