Can I question a BA fact in this thread rather than offer one? Seems quite a nerdy thread so I hope someone can answer.

On this page about the B757 BA claims the 757 is...

Acknowledged as the most reliable aircraft in the world

What exactly does that mean and who acknowledges it?

1) It requires less scheduled maintenance than all other aircraft?
2) It requires less non scheduled maintenance than all other aircraft?
3) It has fewer cancellations and mechanical delays than all other aircraft?
4) If you invite it to a party it will not let you down at the last minute?
5) It doesn't crash as often as the rest of the types in the BA fleet?