Answers · last updated 2026-08-28
What is a Z-score on a flight deal?
Z-score is how many standard deviations a live fare sits below (or above) the route’s recent mean. Z = (price − mean) / σ. NomadFare treats Z ≤ −2 as a deal and Z ≤ −3.5 as an error fare, with percentage-off backups when σ is tiny.
A $400 fare is a deal on a route that usually costs $900, and ordinary on a route that usually costs $420. That is why we do not rank every cheap ticket as Amazing.
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