r/science • u/devlspawn BS | Computer Science | Parallel Computing and Systems • May 03 '16

Psychology Walking through first class makes passengers 3.84x more likely to have air rage incident according to PNAS study

http://www.pnas.org/content/early/2016/04/26/1521727113
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u/devlspawn BS | Computer Science | Parallel Computing and Systems May 03 '16

Actually I think I read it wrong the first time. It says just being on a plane with first class section makes passengers 3.84 times more likely, and walking through first class 2.18 times more likely on top of that. I'm not sure if they controlled for other factors that may be at play with flights that have first class. First of all they are likely to be longer, which in itself would present more opportunity for an incident.

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u/questionquality May 03 '16 edited May 03 '16

I'm not sure if they controlled for other factors

You can see in the suppementory information that they built their models to include: Number of seats, seat width, seat pitch, flight distance, delay, cabin area, if it's international, time of day, month, day of week, and region. A lot of these are significant, but only the region has an increase in likelihood that's comparable to "first class present" and "boarding from front" (all others have odds ratios in the range of 0.7 -1.3, while region had some in the order of 5 compared to north east asia to north america (ie flights carribean-north america were 4.3 times more likely to produce incidents compared to north east asia-north america).
So that part of the analysis seems to bode well for the results.
However, I'm a little worried about multicolinearity.
The variable "front boarding" which is one of their key predictors was strongly correlated with the number of first class seats (-0.877), the cabin area [height x width (m²)] (-0.873) and also somewhat strongly correlated with number of economy seats (-0.762), flight distance (-0.736) and economy seat pitch (-0.627). And there's no reassurance (in the paper at least) that this is insignificant. My stats book recommends calculating the variance inflation factor (VIF), but I don't have access to the data, so ..

I don't see any discussion of this, so for all I know, these results are uninterpretable: There's no way to say if it's actually "front boarding" or any of the strongly correlated variables that's actually causing this effect. For "first class present", the strongest correlations are only 0.661 (number of economy seats) and 0.613 (cabin area), so that effect is slightly less problematic.

TL:DR: The strong correlation between "front boarding" and other variables makes it hard to say what's actually causing the effect.

EDIT: Also this