How we measure

What we look at

Every nonstop long-haul flight SAS flies itself from Copenhagen, Stockholm and Oslo, both directions, every departure date about a year ahead, in Business, Premium Economy and Economy. That is 17 destinations.

• Nonstop only. A trip with a connection sells the same seats as the nonstop flights it is built from. Count both and you count twice.
• Only flights SAS flies itself. Partner seats are another market with other prices. None of that is in these figures.

How often

Continuously. Every flight and date is checked about once a day, the most watched routes more often. That is the page's most important limit: a seat that appears and sells out within a few hours can pass unseen. Every figure about how long seats stay up is therefore a ceiling. Reality is, if anything, faster.

What counts as a release

One continuous spell of availability on one flight, one date, one class. Two adjustments keep it honest, and both changed the answers.

• Seats flicker. Availability disappears and comes back within a few hours. Counting every flicker as a new release would inflate the number. A seat that comes back within 24 hours continues the same spell.
• Finding a seat is not seeing it open. When we start following a route, everything already out shows at once, but it may have been there for months. Counted as releases, that gave a convincing pattern: SAS released seats on Mondays. That was our own first look. So a release only counts if we were already following exactly that flight and date before the seats appeared.

History (has the destination ever had seats) counts everything we have seen. Timing and lifetime count only openings we witnessed.

Seats that were still up

Many seats were bookable when the measuring window closed, so their real lifetime is unknown. Skipping them understates the answer, because the longest-lived seats are exactly the ones still up. We use a statistical method that counts seats that were still up. It matters: the naive way understated Business seats' lifetime by about 40 percent.

What the numbers cannot show

• The window is short. Christmas, the summer peak and the far end of the calendar are not properly measurable yet. Releases more than six months out are undercounted.
• We see availability, not bookings. When seats disappear we do not know whether someone booked them or SAS withdrew them.
• We cannot explain SAS's decisions. We report what SAS's award search showed and when. Why is outside what the numbers can answer, and we do not speculate.
• Coverage has gaps. Limits and the odd outage mean not every flight is checked every round. Where a figure rests on few readings we say so on the page.