All best answered from the previous link.
Originally Posted by
Gonzo
Sorry, I thought when you said data you meant the NTK and emissions databases that the airport uses.
Are you just looking at what points you think each airline has in each category, then adding them up and coming up with a different aggregate? It says individual metric scores are not published, so you’re assuming these scores?
No, no assumptions are being made.
As Heathrow's explanation of the metrics does indeed make clear "
Individual metric scores will not be published". That's to say we can't tell how well or badly an individual airline has performed against specific benchmarks (other than the coarse red/amber/green classification bands).
The only thing we can be sure of is whether Airline X was better/worse than Airline Y for any given metric, for example in the above stats for Oman Air we can tell that 19 airlines performed better than it did on CDAs (but not how much better).
But relative rankings are the basis on which Heathrow says it has derived the "league table" points, so the published rankings are all the information we need in order to be able to check the validity of its results.
Incidentally, since the scores are relative and not absolute, we can't tell either whether an airline has actually improved its performance quarter-on-quarter - all we can know is whether the number of other airlines better/worse than it has gone up or down since the previous quarter (but that's a different issue).
Do you know it’s a pro rata points scheme though? I might have missed it, but I couldn’t see that described on the site
The points values for first and last place are unambiguously defined and "
The final score for each airline is calculated by adding up combinations of an airline’s ranking position for each individual metric and the weighting set for the given metric" strongly implies a direct linear relationship between places lost and points lost so that, for example, an airline halfway down the rankings for a given metric gets half the available points, and so on.
Besides, I can't think of any way that even a grossly skewed (and disingenuously undocumented) "points losts per place" sliding scale would produce the published results, with individual airline aggregate scores inflated by between +17% and +138%.
As the saying goes, if it sounds too good to be true ...